Question 1
Question: 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 |
Answer: 4
Question 2
Question: 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 |
Answer: 4
Question 3
Question: The magnetic field lines due to a straight wire carrying a current are
| 1. | straight |
| 2. | circular |
| 3. | parabolic |
| 4. | elliptical |
Answer: 2
Question 4
Question: 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 |
Answer: 4
Question 5
Question: The magnetic field lines inside a long, current carrying solenoid are nearly
| 1. | straight |
| 2. | circular |
| 3. | parabolic |
| 4. | elliptical |
Answer: 1
Question 6
Question: 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 |
Answer: 3
Question 7
Question: 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 |
Answer: 3
Question 8
Question: 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 |
Answer: 4
Question 9
Question: Who first discovered the relationship between electricity and magnetism?
| 1. | Faraday |
| 2. | Newton |
| 3. | Maxwell |
| 4. | Oersted |
Answer: 4
Question 10
Question: 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 |
Answer: 4
Question 11
Question: 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 |
Answer: 3
Question 12
Question: Which of the following devices works on the principle of electromagnetic induction?
| 1. | Ammeter |
| 2. | Voltmeter |
| 3. | Generator |
| 4. | Galvanometer |
Answer: 3
Question 13
Question: A device used for measuring small currents due to changing magnetic field is known as
| 1. | galvanometer |
| 2. | ammeter |
| 3. | voltmeter |
| 4. | potentiometer |
Answer: 1
Question 14
Question: An electric generator actually acts as
| 1. | source of electric charge |
| 2. | source of heat energy |
| 3. | an electromagnet |
| 4. | a converter of energy |
Answer: 4
Question 15
Question: 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 |
Answer: 2
Question 16
Question: For making a strong electromagnet, the material of the core should be
| 1. | soft iron |
| 2. | steel |
| 3. | brass |
| 4. | copper |
Answer: 1
Question 17
Question: 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 |
Answer: 1
Question 18
Question: 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 |
Answer: 3
Question 19
Question: 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 |
Answer: 2
Question 20
Question: A fuse in an electric circuit acts as a
| 1. | current multiplication |
| 2. | voltage multiplication |
| 3. | power multiplier |
| 4. | safety device |
Answer: 4
Question 21
Question: 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 |
Answer: 1
Question 22
Question: 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 |
Answer: 4
Question 23
Question: Kilowatt-hour is the unit of
| 1. | potential difference |
| 2. | electric power |
| 3. | electrical energy |
| 4. | charge |
Answer: 3
Question 24
Question: 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 |
Answer: 4
