Electronics — Physics STD 12 Science — Question

By a cell a current of 0.9 A flows through 2 ohm resistor and 0.3 A through 7 ohm resistor. The internal resistance of the cell is

(a) 0.5 Ω

(b) 1.0 Ω

(c) 1.2 Ω

(d) 2.0 Ω

The resistance of an incandescent lamp is

(a) Greater when switched off

(b) Smaller when switched on

(c) Greater when switched on

(d) The same whether it is switched off or switched on

You are given a resistance wire of length 50 cm and a battery of negligible resistance. In which of the following cases is largest amount of heat generated

(a) When the wire is connected to the battery directly

(b) When the wire is divided into two parts and both the parts connected to the battery in parallel

(c) When the wire is divided into four parts and all the four connected to the battery in parallel

(d) When only half the wire is connected to the battery

Two capacitors of 1mF  and 2mF  are connected in series, the resultant capacitance will be

(a) 4μF

(b)

(c)

(d) 3 μF

A charged body has an electric flux F associated with it. Now if the body is place inside a conducting shell then the electric flux outside the shell is:

 Which of the following statement is false for the properties of em waves?

An organ pipe, open at both ends, contains

1. Longitudinal stationary waves.
2. Longitudinal travelling waves.
3. Transverse stationary waves.
4. Transverse travelling waves.

Express which of the following setups can be used to verify Ohm’s law

(a)

(b)

(c)

(d)

When half of a lens is wrapped in a black cloth, what will be the effect on the image formed by the lens?

At the centre (t = 0) of Newton's ring arrangement, we observe a: