Electricity: Circuits and their Components — Quiz

Q1. Nihal's group lists 'electric kettle, mixer grinder, toaster, oven and microwave'. Under which heading should these go?

• A. Cooking
• B. Transportation
• C. Communication
• D. Entertainment

Q2. Nihal's class trip in the opening of Chapter 3 was to the

• A. Sardar Sarovar Dam in Gujarat
• B. Bhakra Nangal Dam between Punjab and Himachal Pradesh
• C. Hirakud Dam in Odisha
• D. Tehri Dam in Uttarakhand

Q3. When Ravi slides the switch of a working torch into one position the lamp glows; when he slides it to the other position the lamp does not glow. The two positions are respectively called

• A. OFF and ON
• B. ON and OFF
• C. Open and Closed
• D. Hot and Cold

Q4. When two cells are connected to form a battery for a torchlight, the cells are arranged so that

• A. The positive terminal of one cell touches the positive terminal of the next
• B. The positive terminal of one cell is connected to the negative terminal of the next
• C. Both negative terminals are connected together at the spring side
• D. Each cell is wrapped in plastic to keep its terminals separate

Q5. The 'Fascinating Facts' box in the chapter notes that the term 'battery' is also used for

• A. A single cell, such as the one inside a mobile phone
• B. A group of switches in a house
• C. A bundle of insulated wires
• D. A circuit diagram on paper

Q6. In a small incandescent torch lamp, the two terminals are formed by the

• A. Two ends of the filament wire only
• B. Two coloured wires hanging out of the lamp
• C. Metal case at the base of the lamp and the metal tip at the centre of the base
• D. Glass bulb and the insulator support

Q7. When connecting an incandescent torch lamp to an electric cell

• A. It matters which terminal of the lamp meets the positive terminal of the cell
• B. It does not matter — the lamp glows as long as the circuit is complete
• C. The lamp glows only if the metal tip touches the negative terminal
• D. The lamp glows only if both terminals of the lamp touch the same end of the cell

Q8. While inserting a cell into a cell holder for Activity 3.6, Priya must place the cell so that its

• A. Positive terminal is towards the spring side of the holder
• B. Cap touches the holder's plastic body, not metal
• C. Side wall is in contact with the spring, not the terminals
• D. Negative terminal is towards the spring side of the holder

Q9. Before connecting wires in Activity 3.6, why should about 1 cm of plastic covering be removed from each end of every wire?

• A. So that the wire becomes lighter
• B. So that the metal inside is exposed and can make electrical contact
• C. So that the wire becomes longer and reaches the holder
• D. So that the wire bends easily into a curve

Q10. Sometimes an incandescent lamp does not glow even when correctly connected to a fresh cell. The 'Fascinating Facts' box explains that this is usually because

• A. The cell has become too cold to work
• B. The wires have changed colour due to use
• C. The filament inside the lamp has broken — the lamp has 'fused'
• D. The metal case of the lamp has become an insulator

Q11. An LED is connected to a battery so that its longer wire goes to the positive terminal of the battery and its shorter wire to the negative terminal. The LED will

• A. Not glow because the wires are interchanged
• B. Not glow because LEDs need AC supply
• C. Glow, because current is now flowing in the correct direction through the LED
• D. Burn out instantly

Q12. Vidya first connects an LED so that it glows. She then interchanges the two wires going to the LED, keeping everything else the same. What will she observe?

• A. The LED will glow even more brightly
• B. The cell will become hot and explode
• C. The cell will turn into a switch
• D. The LED will not glow

Q13. When the home-made safety-pin switch is in its 'OFF' position

• A. There is an air gap between its two drawing pins, and the circuit is open
• B. Both drawing pins are short-circuited and the lamp glows brightly
• C. The cell is automatically reversed
• D. The cardboard piece becomes a conductor

Q14. In the standard symbol for a single electric cell, the long line and the short line represent respectively

• A. Filament and metal case
• B. Positive terminal and negative terminal
• C. Switch ON and switch OFF
• D. Conductor and insulator

Q15. In the standard symbol for an LED, the triangle points to the direction in which current can flow, and the two small arrows next to it indicate that

• A. The LED can rotate freely
• B. The LED is also a switch
• C. The LED measures temperature
• D. The LED emits light