Moving Charges and Magnetism — Physics STD 12 Science — Question

The color coding of  earth, live and neutral wire respectively is:

Consider an npn transitor with its base-emitter junction forward biased and collector base junction reverse biased. Which of the following statements are true?

Reciprocal of Impedance is:

The capacity of a parallel plate capacitor increases with the

(a) Decrease of its area	(b) Increase of its distance
(c) Increase of its area	(d) None of the above

Two cells of emf’s approximately 5V and 10V are to be accurately compared using a potentiometer of length 400cm.

Huygens' wave theory is used:

In the circuit as shown in the figure the effective capacitance between A and B is

(a) 3 μF

(b) 2 μF

(c) 4 μF

(d) 8 μF

Magnets A and B are geometrically similar but the magnetic moment of A is twice that of B. If T₁ and T₂ be the time periods of the oscillation when their like poles and unlike poles are kept together respectively, then  will be

(a)

(b)

(c)

(d)

If a glass prism is dipped in water, its dispersive power:

1. Increases.
2. Decreases.
3. Does not change.
4. May increase or decrease depending on whether the angle of the prism is less than or greater than 60°.

Which of the following graphs shows the variation of thermoelectric power with temperature difference between hot and cold junction in thermocouples

(a)

(b)

(c)

(d)