Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

A long solenoid of length L has a mean diameter D. It has n layers of windings of N turns each. If it carries a current ‘i’ the magnetic field at its centre will be(a) Proportional to D(b) Inversely proportional to D(c) Independent of D(d) Proportional to L

The hysterisis curve is studied generally for:

Zener diode acts as a/an:

The function of rectifier is :

Correct exposure for a photographic print is 10 seconds at a distance of one metre from a point source of 20 candela. For an equal fogging of the print placed at a distance of 2 m from a 16 candela source, the necessary time for exposure is(a) 100 sec(b) 25 sec(c) 50 sec   (d) 75 sec

Assertion  :   An aircraft flies along the meridian, the potential at the ends of its wings will be the same.
Reason     : Whenever there is change in the magnetic flux e.m.f. induces.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

The work done in moving a unit positive test charge over a closed path in an electric field is _____________.

The critical angle of a medium with respect to air is 45°. The refractive index of medium is(a) 1.41   (b) 1.2(c) 1.5      (d) 2