Electricity

1

Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of 4Ω in series with a combination of two resistors (8Ω each) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and can withstand a maximum power of 16W without melting. Find the maximum current that can flow through the three resistors.

Read More
2

(i) Consider a conductor of resistance ‘R’, length ‘L’, thickness ‘d’ and resistivity ‘ρ’. Now this conductor is cut into four equal parts. What will be the new resistivity of each of these parts? Why?

Read More
3

Consider the given circuit and find the current flowing in the circuit and potential difference across the 15 Ω resistor when the circuit is closed.

Read More
4

Calculate the equivalent resistance of the following network :

Read More
5

What is electrical resistivity? Derive its SI unit. In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads 100 mA. If the length of the wire is doubled, how will the current in the circuit change? Justify your answer.

Read More
6

Consider the following circuit:

 

What would be the readings of the ammeter and the voltmeter when key is closed? Give reason to justify your answers.

Read More
7

Calculate the total cost of running the following electrical devices in the month of September, if the rate of 1 unit of electricity is Rs 6.00.

  1. Electric heater of 1000 W for 5 hours daily.
  2. Electric refrigerator of 400 W for 10 hours daily.
Read More
8

Write Joule’s law of heating.

Read More
9

Why are alloys commonly used in electrical heating devices? Give reason.

Read More
10

Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.

Read More
11

List the factors on which the resistance of a conductor in the shape of a wire depends.

Read More