Wave Optics — Physics STD 12 Science — Question

The phase difference between input and output voltages of  a CE circuit is

(a) 0o

(b) 90o

(c) 180o

(d) 270o

A thin metal plate P is inserted between the plates of a parallel-plate capacitor of capacitance C in such a way that its edges touch the two plates (figure). The capacitance now becomes:

The stopping potential as a function of the frequency of the incident radiation is plotted for two different photoelectric surfaces A and B. The graphs show that work function of A is

(a) Greater than that of B

(b) Smaller than that of B

(c) Equal to that of B

(d) No inference can be drawn about their work functions from the given graphs

A Zener diode:

Nuclear fusion occur in.

The work functions of metals A and B are in the ratio 1 : 2. If light of frequencies f  and 2f are incident on the surfaces of A and B respectively, the ratio of the maximum kinetic energies of photoelectrons emitted is (f is greater than threshold frequency of A, 2f is greater than threshold frequency of B)

(a) 1 : 1

(b) 1 : 2

(c) 1 : 3

(d) 1 : 4

Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is

(a) No point where electric field is zero

(b) Only one point where potential is zero

(c) Only one point where electric field is zero

(d) a, b

A large nonconducting sheet M is given a uniform charge density. Two uncharged small metal rods A and B are placed near the sheet as shown in figure:

1. M attracts A.
2. M attracts B.
3. A attracts B.
4. B attracts A.

Equal torques act on the discs A and B of the previous problem, initially both being at rest. At a later instant, the linear speeds of a point on the rim of A and another point on the rim of B are v_A and v_B respectively. We have:

1. v_A > v_B
2. v_A = v_B
3. v_A < v_B
4. The relation depends on the actual magnitude of the torques.