List of top Physics Questions

The back emf in a dc motor is maximum when the motor has just been switched on When motor is switched on it has maximum speed

The accelerated motion of an object may be due to change in magnitude of velocity or direction of velocity or both. Acceleration can be produced only by change in the magnitude of the velocity.

: Sun looks reddish at sunrise and sunset. : Sun rays have to pass through a larger distance in atmosphere.

Pascal?? law is the working principle of hydraulic lift Pressure $= \frac{thrust}{arer}$

Moon has no atmosphere. The escape velocity for moon is less than that for earth.

Magnetic lines of force form continuous closed loops Magnetic poles always occur in pairs as north pole and south pole

Magnetic field due to current carrying solenoid is independent of its length and cross-sectional area The magnetic field inside the solenoid is uniform

: Interference is not observed if the two coherent slit sources are broad. : A broad source is equivalent to many narrow slit sources.

Increasing the current sensitivity of a galvanometer necessarily increases the voltage sensitivity. Voltage sensitivity is inversely proportional to current sensitivity.

: In interference and diffraction, light energy is redistributed. : There is no gain or loss of energy, which is consistent with the principle of conservation of energy.

In change of state from solid to liquid the temperature decreases until the entire amount of the solid substance melts. The phenomenon of refreezing is called melting.

In a perfectly inelastic collision the kinetic energy is never conserved. The objects get deformed and stick together in perfectly inelastic collision.

Energy can neither be created nor destroyed. The principle of conservation of energy cannot be proved.

Cooking food is difficult on hills. The boiling point decreases with increase in pressure.

: Bulk modulus if elasticity (K) represents incompressibility of the material. : Bulk modulus of elasticity is proportional to change in pressure.

Balmer series lies in the visible region of electromagnetic spectrum. $\frac {1}{?}=R \bigg [\frac {1}{2^2}- \frac {1}{n^2} \bigg ],$ where $ n=3,4,5 $

: Atom as a whole is electrically neutral. : Atom contains equal amount of positive and negative charges.

: Angle of deviation depends on the angle of prism. : For thin prism, $\delta = (\mu - 1) A$.

An object may fall with a constant velocity. This happens when acceleration of the object is equal to acceleration due to gravity.

Angle and angular displacement are dimensionless quantities. Angle is equal to arc length divided by radius.

An electric motor converts electrical energy to mechanical energy The working of the motor is based on mutual induction

Water flows faster than honey. The coefficient of viscosity of water is less than honey.

: When hot water is poured in a thick glass tumbler then the tumbler breaks : Glass is a bad conductor of heat

: Stress is restoring force per unit area. : Interatomic forces in solids are responsible for the property of elasticity

Surface tension has same units as force gradient Surface tension is the force gradient along the suiface of liquide