Samacheer Kalvi solutions for Science - Term 2 [English] Class 7 TN Board chapter 2 - Electricity [Latest edition]

In the circuit diagram below, 10 units of electric charge move past point x every second What is the current in the circuit ______.

In the circuit shown, which switches (L,M or N) must be closed to light up the bulb?

Small amounts of electrical current are measured in milliampere (mA). How many milliampere are there in 0.25 A ?

In which of the following circuits are the bulb connected in series?

The direction of conventional current is ______ to electron flow.

One unit of coulomb is charge of approximately ______ protons or electrons.

______ is used to measure the electric current.

In conducting materials electrons are ______ bounded with atoms.

S.I. unit of Electrical conductivity of a conductor is ______.

True or False – If False give the correct answer

Electron flow is in the same direction to conventional current flow.

True or False – If False give the correct answer

The fuse wire does not melts whenever there is overload in the wiring.

True or False – If False give the correct answer

In a parallel circuit, the electric components are divided into branches.

True or False – If False give the correct answer

The representation of the electric current is A

True or False – If False give the correct answer

The electrical conductivity of the semiconductor is in between a conductor and an insulator.

Match the following

Water : pipe :: Electric current : ______.

Copper: conductor:: Wood: ______.

Length: metre scale: : Current: ______

milli ampere: micro ampere : : 10-3A : ______.

Assertion (A): Copper is used to make electric wires.

Reason (R): Copper has very low electrical resistance.

Assertion (A): Insulators do not allow the flow of current through themselves.

Reason (R): They have no free charge carriers.

What is the speed of electric current?

What is the S.I unit of electrical conductivity?

Name the device used to generate electricity.

Define fuse.

Name some devices that run using heat effect of electric current

Name few insulators.

What is a battery?

Define an electric current.

Differentiate parallel and serial circuits.

Define electrical conductivity.

Explain the construction and working of an Telephone.

Explain the heating effect of electric current.

Explain the construction and working of a dry cell.

Higher Order Question

A student made a circuit by using an electric cell, a switch, a torch bulb (fitted in the bulb holder), and copper connecting wires. When he turned on the switch, the torch bulb did not glow at all. The student checked the circuit and found that all the wire connections were tight.

• What could be the possible reason for the torch bulb not glowing even when the circuit appears to be complete?

Picture based Question

Three conductors are joined as shown in the diagram

The current in conductor RS is 10 A. The current in conductor QR is 6 A. What will be the current in conductor PR

1. 4 A
2. 6 A
3. 10 A 
4. 16 A

Draw the circuit diagram for the following series connection

Study the electric circuit below. Which of the following switches should be closed so that only two bulbs will light up

Study the three electric circuits below. Each of them has a glass rod (G), a steel rod (S), and a wooden rod (W).

In which of the electric circuits would the bulb not light up.