Electronics — JEE physics STD 12 Science — Question

Assertion : An electric motor will maximum efficient when back e.m.f. is equal to applied e.m.f.
Reason : Efficiency of electric motor is depends only on magnitude of back e.m.f.

Assertion : The refractive index of a prism depends only on the kind of glass of which it is made of and the colour of light
Reason : The refractive index of a prism depends upon the refracting angle of the prism and the angle of minimum deviation.

Assertion : The frequencies of incident, reflected and refracted beam of monochromatic light incident from one medium to another are same.
Reason : The incident, reflected and refracted rays are coplanar

Assertion : Woolen clothes keep the body warm in winter.
Reason : Air is a bad conductor of heat.

Assertion : We can not move even a finger without disturbing all the stars.
Reason : Every body in this universe attracts every other body with a force which is inversely proportional to the square of distance between them.

Assertion : By increasing the diameter of the objective of telescope, we can increase its range.
Reason : The range of a telescope tells us how far away a star of some standard brightness can be spotted by telescope.

Assertion : When a body is dropped or thrown horizontally from the same height, it would reach the ground at the same time.
Reason : Horizontal velocity has no effect on the vertical direction.

Assertion : A pulsor is a source of radio waves which change in terms of intensity at regular interval of time
Reason : A pulsor is a rotating neutron star

Assertion : Electric field outside the conducting wire which carries a constant current is zero.
Reason : Net charge on conducting wire is zero.

Assertion : lt is not possible for a system, unaided by an external agency to transfer heat from a body at lower temperature to another body at higher temperature.
Reason : According to Clausius statement, "No process is possible whose sole result is the transfer of heat from a cooled object to a hotter object.