Please refer to Gravitation Class 11 Physics Exam Questions provided below. These questions and answers for Class 11 Physics have been designed based on the past trend of questions and important topics in your class 11 Physics books. You should go through all Class 11 Physics Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 11 Physics Exam Questions Gravitation
Class 11 Physics students should read and understand the important questions and answers provided below for Gravitation which will help them to understand all important and difficult topics.
Very Short Answer type Questions
Q1.When a stone of mass m is falling on the earth of mass M; find the acceleration of earth if any?
Answer : Force exerted by falling stone on earth, F = mg
Acceleration of earth = F/M = mg/M
Q2.Why G is called a universal constant?
Answer : It is so because the value of G is same for all the pairs of the bodies (big or small) situated anywhere in the universe.
Q3.According to Kepler’s second law the radius vector to a planet from the sun sweeps out equal area in equal interval of time. The law is a consequence of which conservation law.
Answer : Law of Conservation of angular momentum.
Q4.What are the factors which determine ; Why some bodies in solar system have atmosphere and others don’t have?
Answer : The ability of a body (planet) to hold the atmosphere depends on acceleration due to gravity.
Q5.What is the maximum value of gravitational potential energy and where?
Answer : The value of gravitational potential energy is negative and it increases as we move away from the earth and becomes maximum ( zero) at infinity.
Q6.The gravitational potential energy of a body at a distance r from the center of earth is U. What is the weight of the body at that point?
Answer : U = GMm/r = (GM/r2) m=g r m= (mg) r
Q7.A satellite revolving around earth loses height. How will its time period be changed?
Answer : Time period of satellite is given by; T = 2π √(R + h)3/GM Therefore ,T will decrease, when h decreases.
Q8.Should the speed of two artificial satellites of the earth having different masses but the same orbital radius, be the same?
Answer :Yes it is so because the orbital speed of a satellite is independent of the mass of a satellite. Therefore the speeds of the artificial satellite will be of different masses but of the same orbital radius will be the same.
Q9.Can a pendulum vibrate in an artificial satellite?
Answer : No, this is because inside the satellite, there is no gravity ,i.e., g = 0.
As t = 2π√I/g, hence, for g=0 , t = ∝ Thus, the pendulum will not vibrate.
Q10.Why do different planets have different escape speed?
Answer : As, escape speed = √2GM/R therefore its value are different for different planets which are of different masses and different sizes.
Short Answer type Questions
Q1.Show that weight of all body is zero at Centre of earth?
Answer : The value of acceleration due to gravity at a depth d below the surface of earth of radius R is given by ɠ=g(1-d/R).At the center of earth, (dept)d=R; so, ɠ =0.The weight of a body of mass m at the centre of earth =mg’=m x 0=0.
Q2.If a person goes to a height equal to radius of the earth from its surface. What would be his weight relative to that on the earth.
Answer : At the surface of the earth, weight W=mg=GM m/R2.
At height h =R , weight
It means the weight would reduce to one-fourth of the weight on the surface of earth.
Q3. What will be the effect on the time period of a simple pendulum on taking to a mountain?
Ans. The time period of a pendulum, T=2π√I/g , i.e., T= 1/√g .As the value of g is less at mountain than at plane, hence time period of simple pendulum will be more at mountain than at plane though the change will be very small.
