Science & Technology › Physics – UPSC Prelims PYQs

In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?

1. Area of the hole in the lid
2. Temperature of the flame
3. Weight of the lid

Select the correct answer using the code given below.

Consider the following phenomena : 1. 2. 3.

Which of the above is/are the prediction/predictions of Albert Einstein's General Theory of Relativity, often discussed in media ?

In the context of modern scientific research, consider the following statements about ‘IceCube’, a particle detector located at South Pole, which was recently in the news :

1. It is the world’s largest neutrino detector, encompassing a cubic kilometre of ice.
2. It is a powerful telescope to search for dark matter.
3. It is buried deep in the ice.

Which of the statements given above is/are correct?

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

Consider the following phenomena:

1. Size of the sun at dusk
2. Colour of the sun at dawn
3. Moon being visible at dawn
4. Twinkle of stars in the sky
5. Polestar being visible in the sky

Which of the above are optical illusions?

Rainbow is produced when sunlight falls on drops of rain. Which of the following physical phenomena are responsible for this?

1. Dispersion
2. Refraction
3. Internal reflection

Select the correct answer using the codes given below.

The known forces of nature can be divided into four classes, viz., gravity, electromagnetism, weak nuclear force and strong nuclear force. With reference to them, which one of the following statements is not correct?

The efforts to detect the existence of Higgs boson particle have become frequent news in the recent past. What is/are the importance/ importances of discovering this particle?

1. It will enable us to understand as to why elementary particles have mass.
2. It will enable us in the near future to develop the technology of transferring matter from one point to another without traversing the physical space between them.
3. It will enable us to create better fuels for nuclear fission.

Select the correct answer using the codes given below.

A team of scientists at Brookhaven National Laboratory including those from India created the heaviest anti-matter (anti-helium nucleus). What is/are the implication/implications of the creation of anti-matter?

1. It will make mineral prospecting and oil exploration easier and cheaper.
2. It will help probe the possibility of the existence of stars and galaxies made of anti-matter.
3. It will help understand the evolution of the universe.

Select the correct answer using the codes given below :

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?

The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason ?

If a potato is placed on a pure paper plate which is white and unprinted and put in a microwave oven, the potato heats up but the paper plate does not. This is because

India-based Neutrino Observatory is included by the Planning Commission as a mega science project under the 11th Five-Year Plan. In this context, consider the following statements:

1. Neutrinos are chargeless elementary particles that travel close to the speed of light.
2. Neutrinos are created in nuclear reactions of beta decay.
3. Neutrinos have a negligible, but non-zero mass.
4. Trillions of Neutrinos pass through human body every second.

Which of the statements given above are correct?

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

Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury used in the manufacture of these lamps?

Which one of the following types of waves are used in a night vision apparatus ?

Which one among the following has the highest energy ?

In the year 2008,

which one of the following conducted a complex scientific experiment in which sub-atomic particles were accelerated to nearly the speed of light ?

Which one of the following laser types is used in a laser printer?

Consider the following statements:

1. A widely used musical scale called diatonic scale has seven frequencies.
2. The frequency of the note Sa (स) is 256 Hz and that of Ni (नी) is 512 Hz.

Which of the statements given above is/are correct?

How can the height of a person who is six feet tall be expressed (approximately) in nanometres?

A person is sitting in a car which is at rest. The reaction from the road at each of the four wheels of the car is R. When the car runs on a straight level road, how will the reaction at either of the front wheels vary?

Assertion (A): In the visible spectrum of light, red light is more energetic than green light.

Reason (R): The wavelength of red light is more than that of green light.

Assertion (A): Radio waves bend in a magnetic field.

Reason (R): Radio waves are electromagnetic in nature.

Consider the following statements :

1. If magenta and yellow coloured circles intersect, the intersected area will have red colour.
2. If cyan and magenta coloured circles intersect, the intersected area will have blue colour.

Which of the statements given above is/are correct?

Consider the following statements:

1. A flute of smaller length gives waves of lower frequency.
2. Sound travels in rocks in the form of longitudinal elastic waves only.

Which of the statements given above is/are correct?

Four wires of the same material and of the dimensions given below are stretched by equal loads separately. Which one of them will be elongated the maximum?

Assertion (A): A jet aircraft moving at Mach number equal to 1 travels faster at an altitude of 15 km than while moving at Mach number equal to 1 near sea level.

Reason (R): The velocity of sound depends on the temperature of the surrounding medium.

Three identical vessels A, B and C are filled with water, mercury and kerosene respectively up to an equal height. The three vessels are provided with identical taps at the bottom of the vessels. If the three taps are opened simultaneously, then which vessel is emptied first?

In which one among the following is the speed of sound maximum?

There are 8 equidistant points A, B, C, D, E, F, G and H in the clockwise direction on the periphery of a circle. In a time-interval t, a person reaches from A to C with uniform motion while another person reaches the point E from the point B during the same time-interval with uniform motion. Both the persons move in the same direction along the circumference of the circle and start at the same instant. How much time after the start will the two persons meet each other?

Which one of the following is printed on a commonly used fluorescent tube light?

Assertion (A): In our houses, the current in AC electricity line changes direction 60 times per second.

Reason (R): The frequency of alternating voltage supplied is 60 hertz.

A car is running on a road at a uniform speed of 60 km/hr. The net resultant force on the car is

A spherical body moves with a uniform angular velocity ω around a circular path of radius r.

Which one of the following statements is correct?

A weightless rubber balloon is filled with 200 cc of water. Its weight in water is equal to

A person stands at the middle point of a wooden ladder which starts slipping between a vertical wall and the floor of a room, while plane. The path traced by a person standing at the middle point of the slipping ladder is

A hydrogen-inflated polythene balloon is released from the surface of the earth. As the balloon rises to an altitude up in the atmosphere, it will

Consider the following statements:

1. Steam at 100 °C and boiling water at 100 °C contain the same amount of heat.
2. Latent heat of fusion of ice is equal to the latent heat of vaporization of water.
3. In an air-conditioner, heat is extracted from the room air at the evaporator coils and is rejected out at the condenser coils.

Which of these statements is/are correct?

Consider the following statements: A four-wheel vehicle moving on a sharp circular path at high speed will

1. Overturn about its outer wheels.
2. Overturn about its inner wheels.
3. Skid outwards.
4. Skid inwards.

Which of these statements are correct?

Diffusion of light in the atmosphere takes place due to

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

Which one of the following statements is correct?

If the radius of the earth were shrunk by one per cent, its mass remaining the same, the value of ‘g’ on the earth’s surface would

Regarding the atom of a chemical element, the magnetic quantum number refers to

A solid cube just gets completely immersed in water when a 0.2 kg mass is placed on it. If the mass is removed, the cube is 2 cm above the water level. What is the length of each side of the cube?

Consider the following natural phenomena:

1. Terrestrial heating
2. Reflection of light
3. Refraction of light
4. Diffraction of light Due to which of these phenomena is mirage formed?

Consider the following statements:

1. Light of longer wavelength is scattered much more than light of shorter wavelength.
2. The speed of visible light in water is 0.95 times its speed in vacuum.
3. Radio waves are produced by rapidly oscillating electrical currents.
4. To detect over-speeding vehicles, police use the Doppler effect of reflected short radio waves.

Which of these statements are correct?

A hollow sphere of radius R, a hollow cube of side R and a thin circular plate of radius R, made up of the same material, are all heated to 20 °C above room temperature. When left to cool in the room, which of them will reach the room temperature first?

Assertion (A): An iron ball floats on mercury but gets immersed in water.

Reason (R): The specific gravity of iron is more than that of mercury.