Electromagnetic Waves — Physics STD 12 Science — Question

Which of the following are correct for insulators?

Given a current carrying wire of non-uniform cross-section. Which one of the following is constant through out the length of wire ?

By corpuscular theory of light, the phenomenon which can be explained is ____________.

In an experiment, the saturation in the plate current in a diode is observed at 240V. But a student still wants to increase the plate current. It can be done, if

(a) The plate voltage is increased further

(b) The plate voltage is decreased

(c) The filament current is decreased

(d) The filament current is increased

In Young's double slit interference experiment, the slit separation is made 3 fold. The fringe width becomes

(a) 1/3 times

(b) 1/9 times

(c) 3 times

(d) 9 times

The nuclear reaction   (mass of deuteron = 2.0141 a.m.u. and mass of He = 4.0024 a.m.u.) is

(a) Fusion reaction releasing 24 MeV energy

(b) Fusion reaction absorbing 24 MeV energy

(c) Fission reaction releasing 0.0258 MeV energy

(d) Fission reaction absorbing 0.0258 MeV energy

Two ions have equal masses but one is singly-ionised and the other is doubly-ionised. They are projected from the same place in a uniform magnetic field with the same velocity perpendicular to the field.

1. Both ions will move along circles of equal radii.
2. The circle described by the singly-ionised charge will have a radius that is. double that of the other circle.
3. The two circles do not touch each other.
4. The two circles touch each other.

Statement(A): Negative charges always move from a higher potential to lower potential point
Statement (B): Electric potential is vector.

Who first proposed that light was wave-like in character?

One plate of parallel plate capacitor is smaller than other, then charge on smaller plate will be

(a) Less than other

(b) More than other

(c) Equal to other

(d) Will depend upon the medium between them