Vector — JEE physics STD 12 Science — Question

Assertion : A rain drop after falling through some height attains a constant velocity.
Reason : At constant velocity, the viscous drag is just equal to its weight.

Assertion : The mirrors used in search lights are parabolic and not concave spherical.
Reason : In a concave spherical mirror the image formed is always virtual.

Assertion : The possibility of an electric bulb fusing is higher at the time of switching ON and OFF
Reason : Inductive effects produce a surge at the time of switch ON and OFF

Assertion : When a vehicle takes a turn on the road, it travels along a nearly circular path.
Reason : In circular motion, velocity of vehicle remains same.

Assertion : Power developed in circular motion is always zero.
Reason : Work done in case of circular motion is zero.

Assertion : Zener diode works on a principle of breakdown voltage.
Reason : Current increases suddenly after breakdown voltage.

Assertion : Now a days a standard metre is defined as in terms of the wavelength of light.
Reason : Light has no relation with length.

Assertion : The heat supplied to a system is always equal to the increase in its internal energy.
Reason : When a system changes from one thermal equilibrium to another, some heat is absorbed by it.

Assertion : Soft iron is used as a core of transformer.
Reason : Area of hysteresis is loop for soft iron is small.

Assertion : Magnetic moment of helium atom is zero.
Reason : All the electron are paired in helium atom orbitals.