Moving Charges and Magnetism — Physics STD 12 Science — Question

Which can pass through 20 cm thickness of the steel

(a) α -  particles

(b) β - particles

(c) γ-  rays

(d) Ultraviolet rays

A capacitor of capacity  is charged upto V volt and then connected to an uncharged capacitor of capacity  . Then final potential difference across each will be

(a)

(b)

(c)

(d)

A condenser of 2mF capacitance is charged steadily from 0 to 5 Coulomb. Which of the following graphs correctly represents the variation of potential difference across its plates with respect to the charge on the condenser

(a)

(a)

(c)

(d)

An incandescent filament emits a spectrum which is:

Assertion :  The setting sun appears to be red.

Reason     :  Scattering of light is directly proportional to the wavelength.

(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.

In the circuit shown here, what is the value of the unknown resistor R so that the total resistance of the circuit between points P and Q is also equal to R

(a) 3 ohms

(b)

(c) ohms

(d) 10 ohms

Four capacitors are connected as shown in the equivalent capacitance between the points P and Q is

(a) 4 μF

(b)

(c)

(d)

In ballistic galvanometer, the frame on which the coil is wound is non-metallic to

(a) Avoid the production of induced e.m.f.	(b) Avoid the production of eddy currents
(c) Increase the production of eddy currents	(d) Increase the production of induced e.m.f.

To minimise the power loss in the transmission cables connecting the power stations to homes and factories, the transmission cables carry current: