Physics - MOST IMPORTANT UPSC CSE Previous Year Questions

The working principle of a washing machine is

Ball bearings are used in bicycles, cars, etc., because-

A person stands at the middle point of a wooden ladder which starts slipping between a vertical wall and the floor of a room, but in doing it remains in a upward plane. The path traced by a person standing at the middle point of the slipping ladder is:

A simple machine helps a person doing:

Consider the following statements regarding a simple pendulum:

1. When the bob passes the mean position, acceleration is zero.
2. In every oscillation, the pendulum attains a certain velocity twice.
3. During oscillation, at extreme limits, velocity and acceleration are both zero.
4. The amplitude of a common pendulum decreases over time.
   Which of these are correct?

A man jumped at a speed of 5 meters per second from a stationary boat and the boat moved off with the speed of 0.5 meter per second. How many times is the mass of the boat greater than that of the man?

An oil tanker is partially filled with oil and moves forward on a plane road with uniform acceleration. The free surface of oil then:

Consider the following statements :
If there were no phenomenon of capillarity

1. it would be difficult to use a kerosene lamp
2. one would not be able to use a straw to consume a soft drink
3. the blotting paper would fail to function
4. the big trees that we see around would not have grown on the Earth
   Which of the statements given above are correct?

For which one of the following capillarity is not the only reason?

Three identical vessels A, B and C are filled to the same lavel with water, mercury and kerosene respectively. There are similar spouts on the bases of all the three vessels if all the three spouts are opened simultaneously. Which vessels will be empty first.

Two statements are given below. out of which one is the statement (A) and other is the Reason (R).
Statement (A) : with increase in temperature the viscosity of glycerin increases.
Reason (R) : The increase in temperature increases the kinetic energy of molecules.
Which is correct with respect to the above two statements?

The floating of cloud in atmosphere is due to the reason of?

When an air bubble at the bottom of a lake rises to the top, it will:

Consider the following statements:

1. Long wavelength light is scattered more than short wavelength.
2. The speed of visible light in water is 0.95 times that of vacuum.
3. Radio waves are produced by fast oscillating electric current.
4. Police use the reflected short radio wave effect of Doppler to detect overspeeding vehicles.
   Which of these statements are correct?

The normal temperature of human body in Kelvin scale is:

The strip of two metals A and B are firmly attached together as shown in the figure. On heating A expands more than B. If this attached strips is heated, it will take this form.

When water is heated from 0ºC to 10ºC, its volume:

A corked bottle full of water when frozen will break because:

Assertion (A): A piece of copper and a piece of glass are heated to the same temperature. When touched, thereafter, the copper piece appears hotter than the glass piece. Reason (R): The density of copper is more than that of glass.

What is the principle by which a cooling system (Radiator) in a motor car works?