Write the mathematical relation between mobility and drift velocity between mobility and drift velocity of charge carriers in a conductor. Name the mobile charge carriers responsible for conduction of electric current in (a) an electrolyte (b) an ionised gas.

2

(a)

Currents of the order of 0.1 A through the human body are fatal. What causes the death: heating of the body due to electric current or something else?

2

(a)

While making a standard resistance, the coil is made of manganin. The coil is double folded and is wound over a non-conducting frame. Why? 

2

(a)

Two students A and B were asked to pick a resistor of \(15 \ k\Omega\) from a collection of carbon resistors. A picked a resistor with bands of colours: brown, green, orange while B choose a resistor with bands black, green, red. Who picked the correct resistor? Explain.

2

(a)

A voltage of 200 V is applied across a colour-coded carbon resistor with first, second and third ring of blue, black and yellow colours. What is the current flowing through the resistor?

2

(a)

Why is it unsafe to turn a light switch on or off while taking bath?

2

(a)

Lights of a car become dim when the starter is operated. Why?

2

(a)

What is terminal potential difference of a cell? Can its value be greater than the emf of a cell? Explain.

2

(a)

Why is the meter bridge method considered unsuitable for the measurement of very low resistances?

2

(a)

Three identical resistors, each of resistance R, when connected in series with a d.c. source, dissipate power X. If the resistors are connected in parallel to the same d.c. source, how much power will be dissipated?

2

(a)

Under what condition is the heat produced in an electric circuit:
(i) directly proportional
(ii) inversely proportional to the resistance of the circuit?

2

(a)

when is more power delivered to a light bulb, just after it is turned on and the glow of the filament is increasing or after it has been ON for a few seconds and the glow is steady?

2

(a)

Two cells of emf 2E and E and internal resistances 2r and r respectively, are connected in parallel. Obtain the expressions for the equivalent emf and the internal resistance of the combination.

2

(a)

Three resistance 3Ω, 6Ω and 9Ω are connected to a battery. In which of them will the power dissipation be maximum if
a) They are all connected in parallel
b) They are all connected in series Give reason.

2

(a)

Give any two applications super conductors

2

(a)