Electromagnetic Induction — Physics STD 12 Science — Question

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of:

The electrostatic force between the metal plates of an isolated parallel capacitor C having a charge Q and area A is:

Assertion  :  The earth’s magnetic field does not affect the working of a moving coil galvanometer.

Reason     : Earth’s magnetic field is very weak.

(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.

An AC source is rated 220V, 50Hz. The average voltage is calculated in a time interval of 0.01s, It:

The electric power :

Which of the following graphs shows the variation of magnetic induction B with distance r from a long wire carrying current

(a)

(b)

(c)

(d)

When current is passed in antimony-bismuth couple, then

(a) The junction becomes hot when the current is from bismuth to antimony

(b) The junction becomes hot when current flows from antimony to bismuth

(c) Both junctions become hot

(d) Both junctions become cold

The charge on any one of the 2 μF  capacitors and 1 μF  capacitor will be given respectively (in μC ) as

(a) 1, 2

(b) 2, 1

(c) 1, 1

(d) 2, 2

One brass plate is inserted between two charges. The force between two charges will:

Two bar magnets of the same mass, length and breadth but magnetic moments M and 2M respectively, when placed in same position, time period is 3 sec. What will be the time period when they are placed in different position

(a)

(b) 3

(c) 3 sec

(d) 6 sec