1 Which statement is true about the symbol for an electric cell?
- a) It has a longer line representing the negative terminal.
- b) It has a shorter but thicker parallel line representing the positive terminal.
- c) It has a longer line representing the positive terminal.
- d) It has a shorter but thicker parallel line representing the negative terminal.
Answer: c) It has a longer line representing the positive terminal.
Explanation: The longer line in the symbol for an electric cell represents the positive terminal.
2 How are the ‘ON’ and ‘OFF’ positions represented in the symbol for a switch?
- a) ‘ON’ is represented by a circle, and ‘OFF’ is represented by a square.
- b) ‘ON’ is represented by a triangle, and ‘OFF’ is represented by a rectangle.
- c) ‘ON’ is represented by a line, and ‘OFF’ is represented by a zigzag.
- d) ‘ON’ is represented by a closed circle, and ‘OFF’ is represented by an open circle.
Answer: d) ‘ON’ is represented by a closed circle, and ‘OFF’ is represented by an open circle.
Explanation: The ‘ON’ and ‘OFF’ positions are represented by closed and open circles, respectively, in the symbol for a switch.
3 What connects the positive terminal of one cell to the negative terminal of the next cell in a battery?
- a) A metal strip
- b) A plastic rod
- c) A wooden block
- d) A rubber band
Answer: a) A metal strip
Explanation: There is usually a thick wire or a metal strip connecting the positive terminal of one cell to the negative terminal of the next cell in a battery.
4 Which devices use batteries?
- a) Washing machines
- b) Cars
- c) Televisions
- d) Microwave ovens
Answer: c) Televisions
Explanation: Devices such as torches, transistors, toys, and TV remote controls use batteries.
5 What happens when the switch is in the ‘ON’ position and the circuit is complete?
- a) The current flows throughout the circuit instantly.
- b) The circuit becomes open.
- c) The battery gets disconnected.
- d) The circuit becomes incomplete.
Answer: a) The current flows throughout the circuit instantly.
Explanation: When the switch is in the ‘ON’ position, the circuit from the positive terminal of the battery to the negative terminal is complete, and the current flows throughout the circuit instantly.
6 How are electric components represented in circuits?
- a) By colors
- b) By symbols
- c) By numbers
- d) By letters
Answer: b) By symbols
Explanation: Electric components are represented by symbols in circuits.
7 What does the longer line represent in the symbol of an electric cell?
- a) Positive terminal
- b) Negative terminal
- c) Both positive and negative terminals
- d) None of the above
Answer: a) Positive terminal
Explanation: In the symbol of an electric cell, the longer line represents the positive terminal.
8 What connects the positive terminal of one cell to the negative terminal of the next cell?
- a) A wire
- b) A switch
- c) A resistor
- d) A capacitor
Answer: a) A wire
Explanation: The positive terminal of one cell is connected to the negative terminal of the next cell using a wire.
9 What is the purpose of the ‘+’ and ‘-‘ symbols in a battery compartment?
- a) To indicate the size of the battery
- b) To indicate the brand of the battery
- c) To indicate the type of the battery
- d) To help in correctly placing the cells
Answer: d) To help in correctly placing the cells
Explanation: The ‘+’ and ‘-‘ symbols in a battery compartment help in correctly placing the cells by indicating the positive and negative terminals.
10 How can a battery be prepared using multiple cells?
- a) By placing them side by side
- b) By connecting the positive terminals together
- c) By connecting the negative terminals together
- d) By connecting the positive terminal of one cell to the negative terminal of the next cell
Answer: d) By connecting the positive terminal of one cell to the negative terminal of the next cell
Explanation: To prepare a battery using multiple cells, the positive terminal of one cell is connected to the negative terminal of the next cell.
11 What does the filament in an electric bulb do?
- a) Glows when current passes through it
- b) Conducts electricity
- c) Regulates the current flow
- d) Stores electrical energy
Answer: a) Glows when current passes through it
Explanation: The filament in an electric bulb glows when an electric current passes through it.
12 What happens when the switch is in the ‘OFF’ position?
- a) The circuit is complete
- b) The circuit is open
- c) The bulb glows
- d) The current flows throughout the circuit
Answer: b) The circuit is open
Explanation: When the switch is in the ‘OFF’ position, the circuit is incomplete and is said to be open.
13 What caution is given regarding lighted electric bulbs connected to the mains?
- a) They may cause a power outage
- b) They may explode
- c) They may be very hot and cause burns
- d) They may consume too much electricity
Answer: c) They may be very hot and cause burns
Explanation: The caution given is that lighted electric bulbs connected to the mains may be very hot and can cause burns if touched.
14 What material is used for the piece of wire tied between the nails?
- A) Copper wire
- B) Aluminium wire
- C) Silver wire
- D) Nichrome wire
Answer: D) Nichrome wire
Explanation: A piece of nichrome wire is used
15 What are fuses used for in electrical circuits?
- A) To prevent electric current from flowing.
- B) To increase the voltage of the circuit.
- C) To regulate the flow of electric current.
- D) To protect against overheating and possible fires.
Answer: D) To protect against overheating and possible fires.
Explanation: Fuses are safety devices used to prevent damages to electrical circuits and possible fires by breaking the circuit when the current exceeds the safe limit.
16 What is the purpose of using miniature circuit breakers (MCBs) in electrical circuits?
- A) To prevent the flow of electric current.
- B) To increase the resistance in the circuit.
- C) To regulate the voltage of the circuit.
- D) To automatically turn off the circuit when the current exceeds the safe limit.
Answer: D) To automatically turn off the circuit when the current exceeds the safe limit.
Explanation: MCBs are switches that automatically turn off when the current in a circuit exceeds the safe limit.
17 What is the recommended mark to look for on electrical products for conformity to specifications?
- A) ISO mark
- B) ISI mark
- C) CE mark
- D) UL mark
Answer: B) ISI mark
Explanation: Looking for the ISI mark on electrical products, as it is an assurance of conformity to the specifications given on the products.
18 What type of bulbs are considered more electricity efficient than incandescent bulbs?
- A) LED bulbs
- B) Fluorescent bulbs
- C) Halogen bulbs
- D) Tungsten bulbs
Answer: A) LED bulbs
Explanation: LED bulbs consume less electricity compared to incandescent bulbs, fluorescent tubes
19 Hans Christian Oersted noticed the deflection of the compass needle when __________.
- a) a bar magnet is brought near it
- b) an electric current flows through a nearby wire
- c) the switch is moved to the ‘ON’ position
- d) the current flows through a wire wrapped around an iron nail
Answer: b) an electric current flows through a nearby wire
Explanation: Hans Christian Oersted noticed the deflection of the compass needle when an electric current flows through a nearby wire.
20 An electric current behaves like a magnet when __________.
- a) a bar magnet is brought near it
- b) the switch is moved to the ‘ON’ position
- c) it flows through a wire wrapped around an iron nail
- d) the current flows through a wire without any nearby magnets
Answer: c) it flows through a wire wrapped around an iron nail
Explanation: When an electric current flows through a wire wrapped around an iron nail, the wire behaves like a magnet.
21 Electromagnets can lift heavy loads because __________.
- a) they are made of iron
- b) they have a hammer attached to them
- c) they are connected to the terminals of a cell
- d) they can be made very strong
Answer: d) they can be made very strong
Explanation: Electromagnets can be made very strong, allowing them to lift heavy loads.
22 An electric bell consists of an electromagnet and __________.
- a) an iron strip with a hammer
- b) a bar magnet
- c) a contact screw
- d) a coil of wire
Answer: a) an iron strip with a hammer
Explanation: Aan electric bell consists of an electromagnet and an iron strip with a hammer at one end.
23 When the iron strip in an electric bell is in contact with the screw, __________.
- a) the bell does not ring
- b) the current flows through the coil
- c) the hammer strikes the gong
- d) the electromagnet loses its magnetism
Answer: b) the current flows through the coil
Explanation: When the iron strip in an electric bell is in contact with the screw, the current flows through the coil.