Wave Optics — Physics STD 12 Science — Question

The internal resistance of a cell depends on

(a) The distance between the plates	(b) The area of the plates immersed
(c) The concentration of the electrolyte	(d) All the above

Identify the paramagnetic substance

(a) Iron

(b) Aluminium

(c) Nickel

(d) Hydrogen

A parallel plate capacitor is connected to a battery as shown in Fig. Consider two situations:
A: Key K is kept closed and plates of capacitors are moved apart using insulating handle.
B: Key K is opened and plates of capacitors are moved apart using insulating handle. Choose the correct option(s).

A coil develops heat of 800 cal/sec. When 20 volts is applied across its ends. The resistance of the coil is (1 cal = 4.2 joule)

(a) 1.2 Ω

(b) 1.4 Ω

(c) 0.12 Ω

(d) 0.14 Ω

Symbolic representation of photodiode is

(a)

(b)

(c)

(d)

Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon

(a) The currents in the two coils

(b) The rates at which currents are changing in the two coils

(c) Relative position and orientation of the two coils

(d) The materials of the wires of the coils

The maximum intensity of fringes in Young's experiment is I. If one of the slit is closed, then the intensity at that place becomes I_o. Which of the following relation is true ?

(a) I = Io	(b) I = 2Io
(c) I = 4Io	(d) There is no relation between I and Io

An unknown resistance R₁ is connected in series with a resistance of 10 W. This combinations is connected to one gap of a metre bridge while a resistance R₂ is connected in the other gap. The balance point is at 50 cm. Now, when the 10 W resistance is removed the balance point shifts to 40 cm. The value of R₁ is (in ohm)

(a) 60

(b) 40

(c) 20

(d) 10

Identify the wrong statement describing the color code for carbon resistors.