Electric Current and its Effects quiz

In the symbol of a cell, the longer line represents the:

A combination of two or more cells is called a:

Which appliance works on the heating effect of current?

The deflection of a compass needle near a current-carrying wire was discovered by:

A fuse works on the:

The part of a bulb that glows is the:

An electromagnet loses its magnetism when:

Which device is used in place of a fuse in modern homes?

In an electric bell, the hammer is attached to the:

Which bulb wastes the most electricity as heat?

Why is the switch symbol drawn differently in ON and OFF positions? (2 marks)

Why should the positive terminal of one cell be connected to the negative terminal of the next in a battery? (2 marks)

Name two factors on which the heat produced in a wire depends. (2 marks)

Why should we not touch a lighted bulb connected to the mains? (2 marks)

What happens to a compass needle when the current in a nearby wire is switched on and off? (2 marks)

Name the element in an electric heater and the material it is made of. (2 marks)

Give two uses of electromagnets in daily life. (2 marks)

What is the ISI mark? Why should we buy appliances with it? (2 marks)

Why does a fuse wire have a low melting point? (2 marks)

Why are LEDs called energy-efficient? (2 marks)

A battery is made of 4 cells of 1.5 V each joined correctly. Find the total voltage. If one cell is reversed, what is the effective voltage? (3 marks)

A student counts pins picked up by an electromagnet: 10 turns: 2 pins; 20 turns: 5 pins; 30 turns: 8 pins. (i) What pattern do you see? (ii) Predict roughly for 40 turns. (iii) What conclusion can be drawn? (3 marks)

A household uses an incandescent bulb of 60 W for 5 hours daily. It is replaced by an LED bulb of 9 W giving similar light. Find the energy used by each per day in watt-hours and the saving per day. (3 marks)

In a circuit test, a student uses 3 bulbs: A glows bright, B glows dim and C does not glow. Suggest a possible reason for each observation. (3 marks)

A fuse is rated 5 A. An iron draws 4 A and a heater draws 8 A. Which appliance can be used safely on this circuit alone? What will happen if both are switched on together? (3 marks)

Read the passage and answer the questions. A mechanic noticed that the fuse in a house kept melting whenever the heater and the geyser were used together. (i) Why did the fuse melt? (ii) What does this protect the house from? (iii) Suggest a safe solution. (5 marks)

Read the passage and answer the questions. Boojho wound an insulated wire 50 times around an iron nail and connected it to a cell. The nail attracted pins. When he disconnected the cell, the pins fell. (i) What has the nail become? (ii) Why did the pins fall? (iii) How can he make it pick up more pins? (5 marks)

Read the passage and answer the questions. Paheli placed a compass near a wire connected to a cell and switch. When she pressed the switch, the needle moved. (i) Why did the needle move? (ii) Who first observed this effect? (iii) What will happen when the switch is released? (5 marks)

Read the passage and answer the questions. Old houses used incandescent bulbs. Many homes now use LED bulbs, which use less electricity and last longer. (i) Why do incandescent bulbs get hot? (ii) What is the benefit of LEDs? (iii) Why is reducing electricity waste good for the environment? (5 marks)

Read the passage and answer the questions. A school bell stopped ringing. The technician found that the contact screw was not touching the armature strip. (i) What is the role of the contact screw? (ii) Why did the bell stop? (iii) What is the role of the electromagnet in the bell? (5 marks)

Draw a labelled diagram of an electric bell and explain its working. (6 marks)

Describe an activity to make an electromagnet using an iron nail, insulated wire and a cell. Draw the set-up and list two ways to make it stronger. (6 marks)

Explain the heating effect of electric current with examples. Draw a labelled diagram of an electric bulb and explain why the filament glows. (6 marks)

Draw a circuit diagram with a battery of three cells, a switch, a bulb and a fuse. Explain the role of each component. (6 marks)

Describe Oersted's experiment showing the magnetic effect of electric current. Draw the diagram and explain what happens when the current is reversed. (6 marks)