QBManager

ELECTRIC CURRENT AND ITS EFFECTS

303401 A safety device that cuts off the current in a circuit if a sudden heavy current starts flowing in it is:

1 Fuse

2 Ammeter

3 Solenoid

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303402 When the switch of an electric bell is pushed.
0

1 Flow of the current stops through the electromagnet in the bell.

2 Current starts to flow through the electromagnet.

3 Voltage decreases in the circuit.

4 None of the above.

ELECTRIC CURRENT AND ITS EFFECTS

303291 Coils of heating devices are made up of:

1 Mercury

2 Nichrome

3 Copper

4 Tungsten

Explanation:

Nichrome
Most heating elements use Nichrome $\frac{80}{20}$ (80% nickel, 20% chromium) wire, ribbon, or strip.
Nichrome $\frac{80}{20}$ is an ideal material, because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time.
Material beneath this layer will not oxidize, preventing the wire from breaking or burning out.Hence, nichrome is used as heating elements.

ELECTRIC CURRENT AND ITS EFFECTS

303292 The electric current flows from the end of cell marked ‘+’ called the:

1 Negative terminal

2 Positive terminal

3 Electric current

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303401 A safety device that cuts off the current in a circuit if a sudden heavy current starts flowing in it is:

1 Fuse

2 Ammeter

3 Solenoid

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303402 When the switch of an electric bell is pushed.
0

1 Flow of the current stops through the electromagnet in the bell.

2 Current starts to flow through the electromagnet.

3 Voltage decreases in the circuit.

4 None of the above.

ELECTRIC CURRENT AND ITS EFFECTS

303291 Coils of heating devices are made up of:

1 Mercury

2 Nichrome

3 Copper

4 Tungsten

Explanation:

Nichrome
Most heating elements use Nichrome $\frac{80}{20}$ (80% nickel, 20% chromium) wire, ribbon, or strip.
Nichrome $\frac{80}{20}$ is an ideal material, because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time.
Material beneath this layer will not oxidize, preventing the wire from breaking or burning out.Hence, nichrome is used as heating elements.

ELECTRIC CURRENT AND ITS EFFECTS

303292 The electric current flows from the end of cell marked ‘+’ called the:

1 Negative terminal

2 Positive terminal

3 Electric current

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303401 A safety device that cuts off the current in a circuit if a sudden heavy current starts flowing in it is:

1 Fuse

2 Ammeter

3 Solenoid

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303402 When the switch of an electric bell is pushed.
0

1 Flow of the current stops through the electromagnet in the bell.

2 Current starts to flow through the electromagnet.

3 Voltage decreases in the circuit.

4 None of the above.

ELECTRIC CURRENT AND ITS EFFECTS

303291 Coils of heating devices are made up of:

1 Mercury

2 Nichrome

3 Copper

4 Tungsten

Explanation:

Nichrome
Most heating elements use Nichrome $\frac{80}{20}$ (80% nickel, 20% chromium) wire, ribbon, or strip.
Nichrome $\frac{80}{20}$ is an ideal material, because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time.
Material beneath this layer will not oxidize, preventing the wire from breaking or burning out.Hence, nichrome is used as heating elements.

ELECTRIC CURRENT AND ITS EFFECTS

303292 The electric current flows from the end of cell marked ‘+’ called the:

1 Negative terminal

2 Positive terminal

3 Electric current

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303401 A safety device that cuts off the current in a circuit if a sudden heavy current starts flowing in it is:

1 Fuse

2 Ammeter

3 Solenoid

4 None of these

ELECTRIC CURRENT AND ITS EFFECTS

303402 When the switch of an electric bell is pushed.
0

1 Flow of the current stops through the electromagnet in the bell.

2 Current starts to flow through the electromagnet.

3 Voltage decreases in the circuit.

4 None of the above.

ELECTRIC CURRENT AND ITS EFFECTS

303291 Coils of heating devices are made up of:

1 Mercury

2 Nichrome

3 Copper

4 Tungsten

Explanation:

Nichrome
Most heating elements use Nichrome $\frac{80}{20}$ (80% nickel, 20% chromium) wire, ribbon, or strip.
Nichrome $\frac{80}{20}$ is an ideal material, because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time.
Material beneath this layer will not oxidize, preventing the wire from breaking or burning out.Hence, nichrome is used as heating elements.

ELECTRIC CURRENT AND ITS EFFECTS

303292 The electric current flows from the end of cell marked ‘+’ called the:

1 Negative terminal

2 Positive terminal

3 Electric current

4 None of these