Electric Current and its Effects Test

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Electric Current and its Effects Test - 4

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Weekly Quiz Competition

Question 1
1 / -0

When current passes through an electric bulb, its filament glows, but the wire passing current to the bulb does not glow because

A
less current flows through the wire as compared to the filament

B
the wire has more resistance than the filament

C
the wire has less resistance than the filament

D
the filament element has a coating of fluorescent material on it

Solution

The connecting wires has less resistance than the filament of the bulb, so less amount of heat is generated in the connecting wires, whereas large amount of heat is generated in the filament.
Question 2
1 / -0

What will happen if you join the two terminals of a cell without connecting them through a switch or a bulb?

A
The electric cell will burn due to large amount of current.

B
The chemicals in the electric cell get used up very fast.

C
The electric cell, due to the flow of large amounts of current, gets corroded.

D
All of the above

Solution

When we join the two terminals of a cell without connecting them through a switch or a bulb, very large current flows through the circuit and whole of the chemical energy is utilised in a very short duration of time.
Question 3
1 / -0

The strength of an electromagnet can be influenced by

A
increasing the current through the wire

B
increasing the number of loops in the coil

C
changing the core of the coil

D
All of the above

Solution

We can change the magnetic field of an electromagnet by changing the current, the number of turns and the core of the coil.
The greater the current, the greater the magnetic field, the greater the number of turns, the greater the magnetic field.
Question 4
1 / -0

Which of the following statements is correct for the movement of electrons between two points?

A
There should be a temperature difference between the two points.

B
There should be a potential difference between the two points.

C
Both the points must be at the same potential.

D
Electrons can even flow without any temperature or potential differences between the two points.

Solution

There should be a potential difference between the two points of the conductor to flow the charge through the conductor. The greater the potential difference across the two points, the greater the current through the conductor.
Question 5
1 / -0

Voltage can be generated

A
by rubbing certain types of materials against each other

B
by means of chemical reactions

C
using magnetic influence on conductors

D
All of these

Solution

We can generate the voltage across two points by rubbing two materials against each other. By doing this, transfer of electrons can take place. The material which loses the electrons becomes positively charged and the other becomes negatively charged. Hence, we create a voltage.
We can create a voltage by converting chemical energy into electrical energy, e.g. dry cell.
We can create a voltage across the two ends of the rod by moving it through the magnetic field.
Question 6
1 / -0

Read the following statements and choose the correct option.

Statement A: Bulb filament is made of tungsten.
Statement B: Filament should have a low melting point.

A
Both statement A and statement B are correct.

B
Statement A is correct, but statement B is incorrect.

C
Statement A is incorrect, but statement B is correct.

D
Both statements A and B are incorrect.

Solution

Statement A is correct, but statement B is incorrect.
Filament of the bulb should have high melting point.
Question 7
1 / -0

When a fuse is rated 8 A, it means

A
it will not work if current is less than 8 A

B
it has a resistance of 8 ohms

C
it will work only if current is 8 A

D
it will burn if current exceeds 8 A

Solution

A fuse is an electrical safety device that operates to provide over current protection of an electrical circuit When a fuse is rated at 8 A, it means it will burn if current exceeds 8 A.
Question 8
1 / -0

Tungsten is mainly used for making filaments of electric bulbs because of its

A
low cost

B
high melting point

C
high electrical conductivity

D
low thermal conductivity

Solution

Tungsten is mainly used for making filaments of electric bulbs because it has high melting point.
Question 9
1 / -0

In which of the following circuits will the bulb glow?

A
A and B only

B
B and C only

C
A, C, and D only

D
All of them

Solution

Bulbs will glow in circuits A, C and D only as no cell is connected in circuit B.
Question 10
1 / -0

Consider the following circuit and choose the correct combination so that bulb X glows the brightest.

A
Close - S₁, Close - S₂, Open - S₃, Open - S₄

B
Close - S₁, Open - S₂, Close - S₃, Open - S₄

C
Open - S₁, Close - S₂, Open - S₃, Close - S₄

D
Close - S₁, Open - S₂, Open - S₃, Close - S₄

Solution

After closing S₁and S₃, three cells are connected in series, which increases the potential difference across the bulb X, hence it will glow brighter.
Question 11
1 / -0

Consider the following circuit. Which bulb will glow if bulbs E and B are not working?

A
A and C

B
C and D

C
A and D

D
No bulb will glow.

Solution

When E and B are not working, the current will flow through bulbs C and D only; so these bulbs will glow.
Question 12
1 / -0

Rahul designed a circuit consisting of 4 bells, some conductors and insulators, a battery and a switch. After switching on the circuit, he found that only three bells were ringing. By mistake, he had connected an insulator at one of the 4 positions indicated by A, B, C and D.

Where in the circuit was the insulator connected?

A
A

B
B

C
C

D
D

Solution

He had put the insulator at D. So, the resulting circuit will be as shown:

Question 13

1 / -0

Match the two columns and select the correct option.

Column I	Column II
(a) Bulb	(i) Electromagnet
(b) Crane	(ii) Heater coil
(c) Electric iron	(iii) Filament

(a) - (iii), (b) - (ii), (c) - (i)

(a) - (i), (b) - (ii), (c) - (iii)

(a) - (iii), (b) - (i), (c) - (ii)

(a) - (ii), (b) - (iii), (c) - (i)

Solution

Bulb contains filament, crane uses electromagnet and electric iron has heating element.

Question 14

1 / -0

The following diagram shows a simple electric bell with four leads Q, R, S and T. Where should we connect the battery and the connecting wire to get a continuous ringing sound?

Battery	Connecting Wire
(1) Between R and S	Between Q and T
(2) Between Q and S	Between R and S
(3) Between Q and R	Between S and T
(4) Between Q and T	Between R and S

(1)

(2)

(3)

(4)

Solution

Battery should be connected between the extreme terminal of the electromagnet i.e.Q and T and connecting wire should be connected between the inner terminals.

Question 15

1 / -0

The following diagram shows an electric bell:

Which materials are suitable for parts labelled as P, Q and R?

	P	Q	R
(1)	Brass	Soft Iron	Steel Spring
(2)	Soft Iron	Brass	Soft Iron
(3)	Soft Iron	Soft Iron	Steel Spring
(4)	Steel	Brass	Copper Spring

(1)

(2)

(3)

(4)

Solution

The core of the coil should be made of soft iron. Metal rod can be made of soft Iron. Spring should be made of steel because it should be made of an elastic material.

Question 16
1 / -0

What is the difference between the wires used in the elements of an electric heater and a fuse?

A
The resistivity of the wire used in a heater element is high, while a fuse wire has low resistivity.

B
The resistivity of the wire used in a heater element is low, while a fuse wire has high resistivity.

C
The melting point of the wire used in a heater element is high, while a fuse wire has low melting point.

D
The melting point of the wire used in a heater element is low, while a fuse wire has high melting point.

Solution

A fuse wire should have high resistivity and low melting point as fuse melts down to protect the electrical appliances by breaking the circuit when current more than the permissible value passes through it. The wire used in a heater element has high resistivity and high melting point as the heat produced in the element due to large resistivity (hence large resistance) is used to heat the water.
Question 17
1 / -0

What will happen to the strength of magnetic field if we increase the radius of the solenoid?

A
Will increase

B
No change

C
Will decrease

D
Will first increase and then become constant

Solution

Magnetic field inside the solenoid will decrease if we increase the radius of the solenoid.
Question 18
1 / -0

Directions For Questions

Directions: Read the paragraph given below and answer the following question.
An electric source powers the electromagnet used in an electric bell. The switch which you press to sound an electric bell acts as the circuit breaker or the switch which completes the circuit.
When the switch (K) is pressed, the circuit loop is complete, which causes current to flow through the circuit. The arm (A) which strikes the gong (B) is connected to a spring (T) at one end and an iron ball at the other end. This is called a clapper or a striker. The arm is attached to an iron strip (I) which is attracted to the electromagnet (E) when the circuit is complete and current is flowing through it.
This is because the magnetic field created by the electromagnet attracts the iron strip towards it when the circuit is complete.

...view full instructions

What will happen if an iron strip is replaced by a glass strip?

A
The bell will start ringing louder.

B
The bell will not ring at all.

C
The strip will remain attached to the electromagnet.

D
Sometimes the bell will ring, sometimes it will not ring.

Solution

As the glass is not a magnetic material, it will not be attracted by the electromagnet. Hence, the bell will not ring.
Question 19
1 / -0

In which of the following is an electromagnet used?

A
Electric bells

B
Loudspeaker

C
Cranes to pick up cars

D
All of these

Solution

When a soft iron bar is placed inside a solenoid carrying current, it becomes a magnet as long as current flows through the solenoid. Such a magnet is known as an electromagnet. They are used to lift heavy iron pieces. They are fitted on cranes, which lift heavy masses of scrap iron.
They are also used in many devices, like electric bell, electric horn, telephone receiver, electric relay, microphones, television, loudspeakers, etc. Hence, option (4) is correct.
Question 20
1 / -0

Four cells, each of voltage `V` across them, are joined in parallel to form a battery. What will be the equivalent voltage of the battery?

A
V/4

B
4V

C
V

D
Zero

Solution

As the four cells are connected in parallel, the voltage remains the same whatever is the number of cells connected.
Hence, the equivalent voltage will be V.

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Electric Current and its Effects Test - 4

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Electric Current and its Effects Test - 4

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Question 1

less current flows through the wire as compared to the filament

the wire has more resistance than the filament

the wire has less resistance than the filament

the filament element has a coating of fluorescent material on it

Solution

Question 2

The electric cell will burn due to large amount of current.

The chemicals in the electric cell get used up very fast.

The electric cell, due to the flow of large amounts of current, gets corroded.

All of the above

Solution

Question 3

increasing the current through the wire

increasing the number of loops in the coil

changing the core of the coil

All of the above

Solution

Question 4

There should be a temperature difference between the two points.

There should be a potential difference between the two points.

Both the points must be at the same potential.

Electrons can even flow without any temperature or potential differences between the two points.

Solution

Question 5

by rubbing certain types of materials against each other

by means of chemical reactions

using magnetic influence on conductors

All of these

Solution

Question 6

Both statement A and statement B are correct.

Statement A is correct, but statement B is incorrect.

Statement A is incorrect, but statement B is correct.

Both statements A and B are incorrect.

Solution

Question 7

it will not work if current is less than 8 A

it has a resistance of 8 ohms

it will work only if current is 8 A

it will burn if current exceeds 8 A

Solution

Question 8

low cost

high melting point

high electrical conductivity

low thermal conductivity

Solution

Question 9

A and B only

B and C only

A, C, and D only

All of them

Solution

Question 10

Close - S1, Close - S2, Open - S3, Open - S4

Close - S1, Open - S2, Close - S3, Open - S4

Open - S1, Close - S2, Open - S3, Close - S4

Close - S1, Open - S2, Open - S3, Close - S4

Solution

Question 11

A and C

C and D

A and D

No bulb will glow.

Solution

Question 12

A

B

C

D

Solution

Close - S₁, Close - S₂, Open - S₃, Open - S₄

Close - S₁, Open - S₂, Close - S₃, Open - S₄

Open - S₁, Close - S₂, Open - S₃, Close - S₄

Close - S₁, Open - S₂, Open - S₃, Close - S₄