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You have three resistors of values 2Ω, 3Ω and 5Ω. How will you join them so that the total resistance is more than 7Ω?
1) Draw a diagram for the arrangement
2) Calculate the equivalent resistance.
Concept: Potential and Potential Difference
Name two safety devices which are connected to the live wire of a household electric circuit
Concept: Electrical Power
Find the equivalent resistance between A and B

Concept: Resistance of a System of Resistors >> Resistors in Series
State whether the resistivity of a wire changes with the change in the thickness of the wire.
Concept: Potential and Potential Difference
How does an increase in the temperature affect the specific resistance of a :
(i) Metal and
(ii) Semiconductor ?
Concept: Ohm's Law
Calculate the effective resistance across AB?

Concept: Ohm's Law

The diagram above shows a circuit with the key k open. Calculate :
(i) the resistance of the circuit when the key k is open.
(ii) the current drawn from the cell when the key k is open.
(iii) the resistance of the circuit when the key k is closed.
(iv) the current drawn from the cell when the key k is closed.
Concept: Electrical Power
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.

(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
Concept: Electrical Power
(a) Calculate the total resistance across AB.

(b) If a cell of e.m.f 2.4 V with negligible internal resistance is connected across AB then calculate the current drawn from the cell.
Concept: Internal Resistance of a Cell
(a) Observe the diagram given below and state whether the bulb will glow or not when we switch on K.

(b) Is it safe to handle the bulb when the switch is OFF?
(c) Give a reason for your answer in (b).
Concept: Heating Effect of Electric Current
An electric bulb is rated ‘240 V, 100 W’.
- What information can you get from the above statement?
- What will happen if this bulb is connected across 220 V?
- Calculate the resistance of the bulb.
- Also find the energy consumed by the bulb in 10 minutes.
Concept: Electric Resistance
When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.
Concept: Heating Effect of Electric Current
Choose the correct relation for e.m.f. (ε) and terminal voltage V:
Concept: Terminal Voltage of a Cell
'A geyser is rated 240 W-220 V'. Explain the meaning of this statement.
Concept: Power Rating of Common Electrical Appliances
Find the value of current I drawn from the cell.

- Calculate the current I.
- Calculate the terminal voltage.
Concept: Terminal Voltage of a Cell
The potential difference between terminals of a cell in a closed electric circuit is ______.
Concept: Terminal Voltage of a Cell
Sumit does 600 J of work in 10 min and Amit does 300 J of work in 20 min. Calculate the ratio of the powers delivered by them.
Concept: Household Consumption of Electric Energy
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5 bulbs are connected in series in a room. One bulb is fused. It is removed and remaining 4 bulbs are again connected in series to the same circuit. What will be the effect on the following physical quantities? (Increases, Decreases, Remain Same). |
- Resistance
- Intensity of light
Concept: Electric Resistance
A fuse is rated 5 A. Can it be used with a geyser rated 1540 W, 220 V Write Yes or No. Give supporting calculations to justify your answer.
Concept: Electrical Power
