EXERCISE 5

Author:Asok Kumar Das & Chittaranjan Dasgupta

Asok Kumar Das Physics Solutions for EXERCISE 5

Simple step-by-step solutions to EXERCISE 5 questions of Current Electricity from A Text Book of PHYSICS PART 2 : CLASS 12. Also get 3D topic explainers, cheat sheets, and unlimited doubts solving on EMBIBE.

Questions from EXERCISE 5 with Hints & Solutions

EASY
12th West Bengal Board
IMPORTANT

The given graph shows the variation of resistance of mercury in the temperature range O< T< 4K. Name the phenomenon shown by the graph of figure.

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EASY
12th West Bengal Board
IMPORTANT

A secondary cell of emf E is being charged by an external supply. Its terminal voltage during charging is V. Compare E and V.

HARD
12th West Bengal Board
IMPORTANT

The figure, Fig. 5.163 Shows a potentiometer with a cell of 2.0 V And internal resistance 0.40Ω Maintaining a potential.

Question Image

Drop across a resistor wire AB A standard cell which maintains a constant emf of 1.02 V (for very moderate current currents up to a few μA ) gives a balance point at 67.3 cm Length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600kΩ Is put in series with it, which is shorted close to balance point. The standard cell is then replaced by a cell of unknown emf And the balance point found similarly turns out to be at 82.3 cm Length of the wire.

(a) What is the value of ?

MEDIUM
12th West Bengal Board
IMPORTANT

The figure, Fig. 5.163 Shows a potentiometer with a cell of 2.0 V And internal resistance 0.40Ω Maintaining a potential

Question Image

Drop across a resistor wire AB A standard cell which maintains a constant emf of 1.02 V (for very moderate current currents up to a few μA ) gives a balance point at 67.3 cm Length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600kΩ Is put in series with it, which is shorted close to balance point. The standard cell is then replaced by a cell of unknown emf And the balance point found similarly turns out to be at 82.3 cm Length of the wire.

(b) What purpose does the high resistance of 6000kΩ.

EASY
12th West Bengal Board
IMPORTANT

The figure, Fig. 5.163 Shows a potentiometer with a cell of 2.0 V And internal resistance 0.40Ω Maintaining a potential

Question Image

Drop across a resistor wire AB A standard cell which maintains a constant emf of 1.02 V (for very moderate current currents up to a few μA ) gives a balance point at 67.3 cm Length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600kΩ Is put in series with it, which is shorted close to balance point. The standard cell is then replaced by a cell of unknown emf And the balance point found similarly turns out to be at 82.3 cm Length of the wire.

(c) Is the balance point effect by this high resistance?

EASY
12th West Bengal Board
IMPORTANT

The figure, Fig. 5.163 Shows a potentiometer with a cell of 2.0 V And internal resistance 0.40Ω Maintaining a potential

Question Image

Drop across a resistor wire AB A standard cell which maintains a constant emf of 1.02 V (for very moderate current currents up to a few μA ) gives a balance point at 67.3 cm Length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600kΩ Is put in series with it, which is shorted close to balance point. The standard cell is then replaced by a cell of unknown emf And the balance point found similarly turns out to be at 82.3 cm Length of the wire.

(d) Is the balance point affected by the internal resistance of the driver cell?

EASY
12th West Bengal Board
IMPORTANT

The figure, Fig. 5.163 Shows a potentiometer with a cell of 2.0 V And internal resistance 0.40Ω Maintaining a potential

Question Image

Drop across a resistor wire AB A standard cell which maintains a constant emf of 1.02 V (for very moderate current currents up to a few μA ) gives a balance point at 67.3 cm Length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600kΩ Is put in series with it, which is shorted close to balance point. The standard cell is then replaced by a cell of unknown emf And the balance point found similarly turns out to be at 82.3 cm Length of the wire.

(e) Would the method work in the above solution if the driver cell of potentiometer had an emf of 1.0 V Instead of 2.0 V?

MEDIUM
12th West Bengal Board
IMPORTANT

Question Image

The figure, Figure shows a potentiometer with a cell of 2.0 V and internal resistance 0.40 Ω maintaining a potential drop across a resistor wire AB A standard cell which maintains a constant emf of 1.02 V (for very moderate current currents upto a few μA ) gives a balance point at 67.3 cm length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600  is put in series with it, which is shorted close to balance point. The standard cell is then replaced by a cell of unknown emf and the balance point found similarly turns out to be at 82.3 cm length of the wire. Would the circuit work well for determining an extremely small emf, say of the order of a few mV (such as the typical emf of the thermocouple)? If now, how will you modify the circuit.