Physics MCQ Questions  with Answer for all Competitive Exams

Explanation: The resistance offered by the coil due to DC current remains zero hence there be no effect on light emerging from the bulb

Explanation: In the case of an object moving along a circular path two types of forces centripetal and centrifugal act upon it. As they have the opposite impacts thus, the object remains in balance. When centrifugal force gets disturbed then the object will leave the balance and skid toward an outward direction.

Explanation: The sound of the higher pitch will be heard compared to the sound of lower pitch.

Explanation: ​If the doors of a refrigerator are left open for a few hours, the room temperature will increase as heat is merely recycled from the room into the refrigerator and then back into the room. Thus, net room temperature would increase from the heat of the motor that would be constantly running to move energy around in a circle.

Explanation: The electron and proton carry opposite charges but are equal in magnitude hence the forces acting on these particles in a uniform electric field will be equal in magnitude but in opposite direction. Electron and proton differ in mass hence the acceleration will be different in these two particles.

Explanation: By Newton’s second law F = ma. If a = 0, F_net =0 Thus, the resultant force is zero.

Explanation: Torque = Force × perpendicular distance.

SI unit of Torque will be = Newton meter

Explanation: A transformer is a device that is used to increase or decrease the alternating current voltage.

Explanation: ​When light shines on a metal electrons can be ejected from the surface of the metal in the phenomenon known as the photoelectric effect. Einstein received a noble prize for the discovery of the same. ​​While, Compton effect, discovered by Arthur Holly Compton, is the inelastic scattering of a photon by a charged particle, usually an electron. It results in a decrease in energy of the photon called the Compton Effect. ​​The theory of relativity determined that the laws of physics are the same for all non-accelerating observers.

Explanation: ​Infrared is used in the remote control of a television. It has a wavelength greater than visible light (> 800nm) which is invisible to the human eye but can be felt as heat.

Explanation: Air bubbles in water would act as a diverging lens because the Index of refraction of air is less than that of water.

Explanation: Colour photography was discovered by James Clerk Maxwell in 1855. The first demonstration of colour photography by three colour methods was suggested by him in 1855.

Explanation: Myopia is also known as Short-sightedness in which a person can see near objects clearly but cannot see distant objects distinctly.

Explanation: ​Light is made up of wavelengths of light, and each wavelength designates a particular colour. The colour of an object is the wavelengths of light that it reflects and the colour we see is a result of which wavelengths are reflected back to our eyes.

Explanation: The distance-time graph parallels the time axis. ​​

It is clear from the graph that the position of the object is not changing with the change in time, hence the object is at rest, or in other words, we can say that it is a zero velocity motion.

Explanation: Total internal reflection is an optical phenomenon that happens when a ray of light strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal surface. If the refractive index is lower on the other side of the boundary, no light can pass through and all light is reflected. The critical angle is the angle of incidence above which the total internal reflection occurs. Total internal reflection takes place when light travels from an optically denser medium to an optically rarer medium. The Refractive index of diamond is very high (2,417) whereas the refractive index of glass is only in between (1.5 to 1.6), whereas in the rest all options there is no possibility of total internal reflection because of the refractive index of water (1.33) and air (1.0005) islets than the refractive index of glass.

Explanation: As in outer space there is no atmosphere to scatter light. So the sky appears black to an astronaut.

Explanation: A blackbody is a body that absorbs all incident radiations falling on it regardless of the frequency and wavelength of the radiation.

Explanation: ​If no air resistance is present, the rate of descent depends only on how far the object has fallen, no matter how heavy the object is. This means that two objects will reach the ground at the same time if they are dropped simultaneously from the same height. This statement follows the law of conservation of energy. However, if air resistance is present, then the shape of the object becomes important.

Explanation: When a stick is dipped in water, the ray of light that travels from the stick to the observer travels from a denser medium to a rarer medium and bends away from the normal. Thus, every point of the dipped stick produces a vertical image that is slightly above the original position. Thus, the stick appears to be slightly bent and shorter.

Explanation: Air on getting warmer rises up. This air is trapped by the cooling unit on the upward side and made cool.

Explanation: Owls have more rods (which help to see at night) in their eyes and they have large eyes that make it lighter to enter the eyes.

Explanation: The decibel is widely known as a measure of sound pressure level but is also used for a wide variety of other measurements in science and engineering. The decibel is commonly used in acoustics to quantify sound levels relative to a 0 dB reference which has Men defined as a sound pressure level of 0.0002 microbars. The noise level of 100 decibels would correspond to noise from a machine shop.

Explanation: Fibre optics is the science of transmitting data, voice, and images by the passage of light through thin, transparent fibres.

Explanation: As the swing rises, its kinetic energy changes to potential energy; as with height potential energy P.E. = mgh increases. And according to the law of conservation of energy total energy E = K.E + P. E constant.