Thursday, October 25, 2018
How to study Physics on Ashish Kumar - Let's Learn?
In this video, I am explaining the proper way to study physics through my lectures on Ashish Kumar - Let's Learn.
Tuesday, October 16, 2018
What is the Idea and Mission behind Ashish Kumar Let's Learn?
Ashish Kumar – Let’s Learn is committed to
developing the variegation
of India’s higher education to help students find their “Best Result.”
This educational platform promotes higher
education to students around India by offering free, accurate,
comprehensive online training for Mathematics & Physics.
Idea behind Ashish Kumar – Let’s Learn
The idea behind Ashish Kumar – Let’s Learn is to
work continuously to support and improve teaching standards. We achieve this
aim by utilizing Information and Educational Resources, and by enabling students
to get the best content, notes and videos together in one place and create an
environment in which that video lectures and notes are easily accessible to
develop their online learning skills and expertise.
Our Mission
Our mission is to standardize education through
the submission of world-class higher education that are flexible, accessible and
prudential. Using the latest technological innovation and teaching methods, and
Virtually anyone with an internet connection and a commitment to self-indulgence
can explore free online video lectures, books and highly engaging educational resources.
Thursday, October 4, 2018
Example 28 | Chapter 3 | Class 11 | Trigonometry Functions | NCERT Solut...
#FreeClasses #Mathematics #Homeschool #homeschooling #elearning #ncertsolutions #AshishKumarLetsLearn
5(G) || Exercise 5.5 (Q4 to Q11) Continuity And Differentiability Class 12 Maths
In this lecture, I am discussing differentiation using logarithm through Practice Questions from NCERT Exercise 5.5 ( Question 4 to Question 11) Continuity And Differentiability Class 12 Maths
#ContinuityAndDifferentiability #Class12Maths #AshishKumarLetsLearn #homeschool #homeschooling #mathematics #elearning #education #learning #tutorials
Tuesday, October 2, 2018
Monday, September 24, 2018
6(I) || Theorem 6.7 Theorem 6.8 Theorem 6.9 Chapter 6 Triangles Class 10...
Theorem 6.7 : If a perpendicular is drawn from the vertex of the right angle of a right triangle to the hypotenuse then triangles on both sides of the perpendicular are similar to the whole triangle and to each other.
Theorem 6.8 : In a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
Theorem 6.9 : In a triangle, if square of one side is equal to the sum of the squares of the other two sides, then the angle opposite the first side is a right angle.
Sunday, September 23, 2018
Sunday, September 16, 2018
5(B) || Modulus, Argument, Polar Form || Exercise 5.2 || Complex Numbers...
In this lecture, I am discussing graphical representation of complex numbers on Cartesian Coordinate System and Polar Coordinate System.
Tuesday, September 11, 2018
Sunday, September 2, 2018
Sunday, August 26, 2018
Saturday, August 25, 2018
Friday, August 24, 2018
1(K) | Exercise 2.7 to 2.15 | Units and Measurements | Physics | Class 11
Question 2.7 A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair ?
Question 2.8 Answer the following : (a)You are given a thread and a metre scale. How will you estimate the diameter of the thread ?
(b)A screw gauge has a pitch of 1.0 mm and 200 divisions on the circular scale. Do you think it is possible to increase the accuracy of the screw gauge arbitrarily by increasing the number of divisions on the circular scale ?
(c) The mean diameter of a thin brass rod is to be measured by vernier callipers. Why is a set of 100 measurements of the diameter expected to yield a more reliable estimate than a set of 5 measurements only ?
Question 2.9 The photograph of a house occupies an area of 1.75 cm2 on a 35 mm slide. The slide is projected on to a screen, and the area of the house on the screen is 1.55 m2. What is the linear magnification of the projector-screen arrangement.
Question 2.11 The length, breadth and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.
Question 2.12 The mass of a box measured by a grocer’s balance is 2.300 kg. Two gold pieces of masses 20.15 g and 20.17 g are added to the box. What is (a) the total mass of the box, (b) the difference in the masses of the pieces to correct significant figures ?
Question 2.13 A physical quantity P is related to four observables a, b, c and d as follows :The percentage errors of measurement in a, b, c and d are 1%, 3%, 4% and 2%, respectively. What is the percentage error in the quantity P ? If the value of P calculated using the above relation turns out to be 3.763, to what value should you round off the result ?
Question 2.14 A book with many printing errors contains four different formulas for the displacement y of a particle undergoing a certain periodic motion : (a) y = a sin 2Ï€ t/T (b) y = a sin vt (c) y = (a/T) sin t/a (d) y a
= ( 2 ) (sin 2 / + cos 2 / ) πt T π t T
(a = maximum displacement of the particle, v = speed of the particle. T = time-period of motion). Rule out the wrong formulas on dimensional grounds.
Question 2.15 A famous relation in physics relates ‘moving mass’ m to the ‘rest mass’ mo of a
particle in terms of its speed v and the speed of light, c. (This relation first arose as a consequence
of special relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant c. He writes :
Tuesday, August 21, 2018
3(K) | Exercise 3.8, 3.9, 3.10, 3.11, 3.12 | Motion in a Straight Line |...
Question 3.9
Two towns A and B are connected by a regular bus service with a bus leaving in either direction every T minutes. A man cycling with a speed of 20 km h–1 in the direction A to B notices that a bus goes past him every 18 min in the direction of his motion, and every 6 min in the opposite direction. What is the period T of the bus service and with what speed (assumed constant) do the buses ply on the road?
Question 3.10 A player throws a ball upwards with an initial speed of 29.4 m s–1 .
(a) What is the direction of acceleration during the upward motion of the ball ? (b) What are the velocity and acceleration of the ball at the highest point of its motion ?
(c) Choose the x = 0 m and t = 0 s to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.
(d) To what height does the ball rise and after how long does the ball return to the player’s hands ? (Take g = 9.8 m s–2
and neglect air resistance).
Question 3.11 Read each statement below carefully and state with reasons and examples, if it is true or false ;
A particle in one-dimensional motion (a) with zero speed at an instant may have non-zero acceleration at that instant (b) with zero speed may have non-zero velocity, (c) with constant speed must have zero acceleration, (d) with positive value of acceleration must be speeding up.
Question 3.12 A ball is dropped from a height of 90 m on a floor. At each collision with the floor, the ball loses one tenth of its speed. Plot the speed-time graph of its motion between t = 0 to 12 s.
#FreeClasses #MathsAndPhysics #AshishKumarLetsLearn #CompleteSyllabus #AshishKumar #NCERT
3(L) | Exercise 3.13 to 3.22 | Motion in a Straight Line | Class 11 | Ph...
Question 3.13 Explain clearly, with examples, the distinction between : (a) magnitude of displacement (sometimes called distance) over an interval of time, and the total length of path covered by a particle over the same interval;
(b) magnitude of average velocity over an interval of time, and the average speed over the same interval. Average speed of a particle over an interval of time is defined as the total path length divided by the time interval. Show in both (a) and (b) that the second quantity is either greater than or equal to the first. When is the equality sign true ? For simplicity, consider one-dimensional motion only.
Question 3.14 A man walks on a straight road from his home to a market 2.5 km away with a speed of 5 km h–1. Finding the market closed, he instantly turns and walks back home with a speed of 7.5 km h–1. What is the (a) magnitude of average velocity, and (b) average speed of the man over the interval of time (i) 0 to 30 min, (ii) 0 to 50 min, (iii) 0 to 40 min ? Note: You will appreciate from this exercise why it is better to define average speed as total path length divided by time, and not as magnitude of average velocity. You would not like to tell the tired man on his return home that his average speed was zero !
Question 3.15 In Exercises 3.13 and 3.14, we have carefully distinguished between average speed and magnitude of average velocity. No such distinction is necessary when we consider instantaneous speed and magnitude of velocity. The instantaneous speed is always equal to the magnitude of instantaneous velocity. Why ?
Question 3.16 Look at the graphs (a) to (d) (Fig. 3.20) carefully and state, with reasons, which of these cannot possibly represent one-dimensional motion of a particle.
Question 3.17 Figure 3.21 shows the x-t plot of one-dimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for t 0 and on a parabolic path for t 0 ? If not, suggest a suitable physical context for this graph.
Question 3.18 A police van moving on a highway with a speed of 30 km h–1 fires a bullet at a thief’s car speeding away in the same direction with a speed of 192 km h–1 the muzzle speed of the bullet is 150 m s–1 , with what speed does the bullet hit the thief’s car ? Note: Obtain that speed which is relevant for damaging the thief’s car
Question 3.19 Suggest a suitable physical situation for each of the following graphs:
Question 3.20 Figure 3.23 gives the x-t plot of a particle executing one-dimensional simple harmonic motion. (You will learn about this motion in more detail in Chapter14). Give the signs of position, velocity and acceleration variables of the particle at t = 0.3 s, 1.2 s, – 1.2 s.
Question 3.21 Figure 3.24 gives the x-t plot of a particle in one-dimensional motion. Three different equal intervals of time are shown. In which interval is the average speed greatest, and in which is it the least ? Give the sign of average velocity for each interval.
Question 3.22 Figure 3.25 gives a speed-time graph of a particle in motion along a constant direction. Three equal intervals of time are shown. In which interval is the average acceleration greatest in magnitude ? In which interval is the average speed greatest ? Choosing the positive direction as the constant direction of motion, give the signs of v and a in the three intervals. What are the accelerations at the points A, B, C and D ?
#FreeClasses #Maths #Physics #AshishKumarLetsLearn #CompleteSyllabus #AshishKumar #NCERT
1(K) | Exercise 2.7 to 2.15 | Units and Measurements | Physics | Class 11
Question 2.7 A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair ?
Question 2.8 Answer the following : (a)You are given a thread and a metre scale. How will you estimate the diameter of the thread ?
(b)A screw gauge has a pitch of 1.0 mm and 200 divisions on the circular scale. Do you think it is possible to increase the accuracy of the screw gauge arbitrarily by increasing the number of divisions on the circular scale ?
(c) The mean diameter of a thin brass rod is to be measured by vernier callipers. Why is a set of 100 measurements of the diameter expected to yield a more reliable estimate than a set of 5 measurements only ?
Question 2.9 The photograph of a house occupies an area of 1.75 cm2 on a 35 mm slide. The slide is projected on to a screen, and the area of the house on the screen is 1.55 m2. What is the linear magnification of the projector-screen arrangement.
Question 2.11 The length, breadth and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.
Question 2.12 The mass of a box measured by a grocer’s balance is 2.300 kg. Two gold pieces of masses 20.15 g and 20.17 g are added to the box. What is (a) the total mass of the box, (b) the difference in the masses of the pieces to correct significant figures ?
Question 2.13 A physical quantity P is related to four observables a, b, c and d as follows :The percentage errors of measurement in a, b, c and d are 1%, 3%, 4% and 2%, respectively. What is the percentage error in the quantity P ? If the value of P calculated using the above relation turns out to be 3.763, to what value should you round off the result ?
Question 2.14 A book with many printing errors contains four different formulas for the displacement y of a particle undergoing a certain periodic motion : (a) y = a sin 2Ï€ t/T (b) y = a sin vt (c) y = (a/T) sin t/a (d) y a
= ( 2 ) (sin 2 / + cos 2 / ) πt T π t T
(a = maximum displacement of the particle, v = speed of the particle. T = time-period of motion). Rule out the wrong formulas on dimensional grounds.
Question 2.15 A famous relation in physics relates ‘moving mass’ m to the ‘rest mass’ mo of a
particle in terms of its speed v and the speed of light, c. (This relation first arose as a consequence
of special relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant c. He writes :
#FreeClasses #MathsAndPhysics #NCERT #Exemplar #AshishKumarLetsLearn #CompleteSyllabus
Saturday, August 18, 2018
7(B) | Exercise 7.3 | Permutations and Combinations | Class 11 | Maths
Question 1. How many 3-digit numbers can be formed by using the digits 1 to 9 if no digit is repeated?
Question 2. How many 4-digit numbers are there with no digit repeated?
Question 3. How many 3-digit even numbers can be made using the digits 1, 2, 3, 4, 6, 7, if no digit is repeated?
Question 4. Find the number of 4-digit numbers that can be formed using the digits 1, 2, 3, 4, 5 if no digit is repeated. How many of these will be even?
Question 5. From a committee of 8 persons, in how many ways can we choose a chairman and a vice chairman assuming one person can not hold more than one position?
Question 8. How many words, with or without meaning, can be formed using all the letters of the word EQUATION, using each letter exactly once?
Question 9. How many words, with or without meaning can be made from the letters of the word MONDAY, assuming that no letter is repeated, if. (i) 4 letters are used at a time,
(ii) all letters are used at a time, (iii) all letters are used but first letter is a vowel?
3(J) | Exercise 3.8 | Motion in a Straight Line | Class 11 | Physics Numericals
Question 3.8
On a two-lane road, car A is travelling with a speed of 36 km h–1. Two cars B and C approach car A in opposite directions with a speed of 54 km h–1 each. At a certain instant, when the distance AB is equal to AC, both being 1 km, B decides to overtake A before C does. What minimum acceleration of car B is required to avoid an accident ?
Sunday, August 12, 2018
13(C) | Supplementary Exercise | LIMITS AND DERIVATIVES | Class 11 | Cha...
In this lecture, I am discussing Question 15, Question 22 of Exercise 13.1, few non-NCERT questions following by NCERT Supplementary Exercise 13.5 of Chapter 13 Limits and Derivatives.
#FreeClasses #MathsAndPhysics #NCERT #Exemplar #AshishKumarLetsLearn #AshishKumar
3(H) | Relative Velocity, Example 3.9, Exercise 3.1, 3.2, 3.3 | Motion i...
Example 3.9 Two parallel rail tracks run north-south. Train A moves north with a speed of 54 km h–1 with a speed of 90 km h–1 , and train B moves south . What is the (a) velocity of B with respect to A ?, (b) velocity of ground with respect to B ?, and (c) velocity of a monkey running on the roof of the train A against its motion (with a velocity of 18 km h–1 with respect to the train A) as observed by a man standing on the ground ?
Exercise 3.1
In which of the following examples of motion, can the body be considered approximately a point object: (a) a railway carriage moving without jerks between two stations. (b) a monkey sitting on top of a man cycling smoothly on a circular track. (c) a spinning cricket ball that turns sharply on hitting the ground. (d) a tumbling beaker that has slipped off the edge of a table.
Exercise 3.2
The position-time (x-t) graphs for two children A and B returning from their school O to their homes P and Q respectively are shown in Fig. 3.19. Choose the correct entries in the brackets below ; (a) (A/B) lives closer to the school than (B/A) (b) (A/B) starts from the school earlier than (B/A) (c) (A/B) walks faster than (B/A) (d) A and B reach home at the (same/different) time (e) (A/B) overtakes (B/A) on the road (once/twice).
Exercise 3.3
A woman starts from her home at 9.00 am, walks with a speed of 5 km h–1 on a straight road up to her office 2.5 km away, stays at the office up to 5.00 pm, and returns home by an auto with a speed of 25 km h–1. Choose suitable scales and plot the x-t graph of her motion.
#FreeClasses #MathsAndPhysics #AshishKumarLetsLearn #CompleteSyllabus #AshishKumar #NCERT
5(D) | Exercise 5.4 & Exercise 5.5 (1, 2, 3) | Continuity & Differentiab...
In this lecture, I am discussing derivative of logarithmic and exponential functions following by NCERT Exercise 5.4 and 5.5.
#FreeClasses #MathsAndPhysics #AshishKumarLetsLearn #CompleteSyllabus #AshishKumar #NCERT
Saturday, August 4, 2018
��Online Lecture - 9(A) | APPLICATIONS OF TRIGONOMETRY | Class 10 | Maths
In this lecture, I am discussing basics of Applications of Trigonometry and following questions from NCERT Exercise 9.1
#FreeClasses #MathsAndPhysics #NCERT #Exemplar #AshishKumarLetsLearn #CompleteSyllabus
��Online Lecture - 4(A) | Class 11 | Mathematics | Chapter 4 | PRINCIPLE ...
In this lecture, I am discussing about Principle Of Mathematical Induction, based on Chapter 4 of NCERT Mathematics Textbook, following by solutions of following questions from Exercise 4.1 :
Question 1
Question 2
Question 3
Question 4
Question 5
#FreeClasses #MathsAndPhysics #NCERT #Exemplar #AshishKumarLetsLearn #AshishKumar
Friday, August 3, 2018
�� NCERT Example 3.1 | PHYSICS Questions | Chapter 3 | CLASS 11
A car is moving along a straight line, say OP in Fig. 3.1. It moves from O to P in 18 s and returns from P to Q in 6.0 s. What are the average velocity and average speed of the car in going (a) from O to P ? and (b) from O to P and back to Q ?
#FreeClasses #MathsAndPhysics #AshishKumarLetsLearn #CompleteSyllabus #AshishKumar #physics
��Online Lecture 3(B) | PHYSICS | Class 11 | KINEMATICS
In this lecture, I am discussing various numericals based on distance, displacement, vector, average speed and average velocity.
#FreeClasses #MathsAndPhysics #AshishKumarLetsLearn #CompleteSyllabus #AshishKumar
��Online Lecture - 2(B) | Class 12 | Mathematics | Chapter 2 | INVERSE TR...
In this lecture, I am discussing derivations of various inverse trigonometry identities and NCERT Exercise 2.2 solutions. #FreeClasses #MathsAndPhysics #AshishKumarLetsLearn #CompleteSyllabus
Saturday, July 28, 2018
��Online Lecture - 4(K) | Class 12 | Mathematics | Chapter 4 | DETERMINANTS
In this lecture, I am discussing practice questions from miscellaneous exercise of chapter 4 class 12.
�� NCERT Example 2.13 | PHYSICS Questions | Chapter 2 | CLASS 11
Example 2.13 Each side of a cube is measured to be 7.203 m. What are the total surface area and the volume of the cube to appropriate significant figures?
��Online Lecture 8(B) | BINOMIAL THEOREM | Class 11
In this lecture, I am discussing practice questions from NCERT Exercise 8.1 of Class 11.
#AshishKumar #AshishKumarLetsLearn #BinomialTheorem #Binomial #Class11 #Maths #OnlineMathsClasses
��Online Lecture 7(B) | COORDINATE GEOMETRY | Class 10
In this video, I am discussing practice questions from NCERT Execise 7.1 of class 10.
Sunday, July 22, 2018
Subscribe to:
Posts (Atom)