| Question (1):
A magnetic field line is used to find the direction of |
| 1. |
south-north
|
| 2. |
a bar magnet
|
| 3. |
a compass needle |
| 4. |
magnetic field |
|
| Ans: 4 |
|
Question (2):
An electric current passes through a straight wire in the direction of south to north. Magnetic compasses are placed at points A and B as shown in the figure.
What is your observation?
|
| 1. |
The needle will not deflect
|
| 2. |
Only one of the needles will deflect
|
| 3. |
Both the needles will deflect in the same direction |
| 4. |
The needles will deflect in the opposite directions |
|
| Ans: 4 |
|
| Question (3):
The magnetic field lines due to a straight wire carrying a current are |
| 1. |
straight
|
| 2. |
circular
|
| 3. |
parabolic |
| 4. |
elliptical |
|
| Ans: 2 |
|
| Question (4):
Magnetic field produced at the centre of a current carrying circular wire is |
| 1. |
directly proportional to the square of the radius of the circular wire
|
| 2. |
directly proportional to the radius of the circular wire
|
| 3. |
inversely proportional to the square of the radius of the circular wire |
| 4. |
inversely proportional to the radius of the circular wire |
|
| Ans: 4 |
|
| Question (5):
The magnetic field lines inside a long, current carrying solenoid are nearly |
| 1. |
straight
|
| 2. |
circular
|
| 3. |
parabolic |
| 4. |
elliptical |
|
| Ans: 1 |
|
| Question (6):
A soft iron bar is introduced inside a current carrying solenoid. The magnetic field inside the solenoid |
| 1. |
will become zero
|
| 2. |
will decrease
|
| 3. |
will increase |
| 4. |
will remain unaffected |
|
| Ans: 3 |
|
| Question (7):
The direction of the force on a current-carrying wire placed in a magnetic field depends on |
| 1. |
the direction of the current
|
| 2. |
the direction of the field
|
| 3. |
the direction of current as well as field |
| 4. |
neither the direction of current nor the direction of field |
|
| Ans: 3 |
|
| Question (8):
The direction of induced curent is obtained by |
| 1. |
Fleming's left-hand rule
|
| 2. |
Maxwell's right-hand thumb rule
|
| 3. |
Ampere's rule |
| 4. |
Fleming's right-hand rule |
|
| Ans: 4 |
|
| Question (9):
Who first discovered the relationship between electricity and magnetism? |
| 1. |
Faraday
|
| 2. |
Newton
|
| 3. |
Maxwell |
| 4. |
Oersted |
|
| Ans: 4 |
|
| Question (10):
In an electric motor, the energy transformation is from |
| 1. |
electrical to chemical
|
| 2. |
chemical to light
|
| 3. |
mechanical to electrical |
| 4. |
electrical to mechanical |
|
| Ans: 4 |
|
| Question (11):
A commutator changes the direction of current in the coil of |
| 1. |
a DC motor
|
| 2. |
a DC motor and an AC generator
|
| 3. |
a DC motor and a DC generator |
| 4. |
an AC generator |
|
| Ans: 3 |
|
| Question (12):
Which of the following devices works on the principle of electromagnetic induction? |
| 1. |
Ammeter
|
| 2. |
Voltmeter
|
| 3. |
Generator |
| 4. |
Galvanometer |
|
| Ans: 3 |
|
| Question (13):
A device used for measuring small currents due to changing magnetic field is known as |
| 1. |
galvanometer
|
| 2. |
ammeter
|
| 3. |
voltmeter |
| 4. |
potentiometer |
|
| Ans: 1 |
|
| Question (14):
An electric generator actually acts as |
| 1. |
source of electric charge
|
| 2. |
source of heat energy
|
| 3. |
an electromagnet |
| 4. |
a converter of energy |
|
| Ans: 4 |
|
| Question (15):
Electromagnetic induction is the |
| 1. |
charging of a body with a positive charge
|
| 2. |
production of current by relative motion between a magnet and a coil
|
| 3. |
rotation of the coil of an electric motor |
| 4. |
generation of magnetic field due to a current carrying solenoid |
|
| Ans: 2 |
|
| Question (16):
For making a strong electromagnet, the material of the core should be |
| 1. |
soft iron
|
| 2. |
steel
|
| 3. |
brass |
| 4. |
copper |
|
| Ans: 1 |
|
| Question (17):
Magnetic field inside a long solenoid carrying current is |
| 1. |
same at all points (uniform)
|
| 2. |
different at poles and at the centre
|
| 3. |
zero |
| 4. |
different at all points |
|
| Ans: 1 |
|
| Question (18):
You have a coil and a bar magnet. You can produce an electric current by |
| 1. |
moving the magnet but not the coil
|
| 2. |
moving the coil but not the magnet
|
| 3. |
moving either the magnet or the coil |
| 4. |
using another DC source |
|
| Ans: 3 |
|
| Question (19):
Which of the following describes the common domestic power supplied in India? |
| 1. |
220 V, 100 Hz
|
| 2. |
220 V, 50 Hz
|
| 3. |
110 V, 100 Hz |
| 4. |
100 V, 50 Hz |
|
| Ans: 2 |
|
| Question (20):
A fuse in an electric circuit acts as a |
| 1. |
current multiplication
|
| 2. |
voltage multiplication
|
| 3. |
power multiplier |
| 4. |
safety device |
|
| Ans: 4 |
|
| Question (21):
The magnetic lines of force inside a current carrying solenoid are |
| 1. |
along the axis and parallel to each other
|
| 2. |
perpendicular to the axis and parallel to each other
|
| 3. |
circular and do not intersect each other |
| 4. |
circular and intersect each other |
|
| Ans: 1 |
|
| Question (22):
When the main switch of the house is put off, it disconnects |
| 1. |
live wire
|
| 2. |
neutral wire
|
| 3. |
earth wire |
| 4. |
live and neutral wires |
|
| Ans: 4 |
|
| Question (23):
Kilowatt-hour is the unit of |
| 1. |
potential difference
|
| 2. |
electric power
|
| 3. |
electrical energy |
| 4. |
charge |
|
| Ans: 3 |
|
| Question (24):
When a fuse is rated 8A, it means |
| 1. |
it will not work if current is less than 8A
|
| 2. |
it has a resistance of 8
|
| 3. |
it will work only if current is 8A |
| 4. |
it will burn if current exceeds 8A |
|
| Ans: 4 |
|
