MAGNETISM AND EMI
CLASS: X
1. When a bar magnet is broken into two pieces :
(A) we will have a single pole on each piece (B) each piece will have two unlike poles
(C) each piece will have two like poles (D) None of these
2. The magnetic field intensity produced due to a current carrying coil is maximum at :
(A) any point (B) any point lying on the axis of the coil (C) points lying between centre of the coil and its circumference (D) none of these
3. The direction of magnetic lines of force produced by passing a direct current in a conductor is :
(A) perpendicular to the conductor & coming outwards
(B) parallel to conductor
(C) surrounding the conductor and of circular nature
(D) perpendicular to the conductor & coming inwards
4. Which of the following statement is not correct about two parallel conductors carrying equal currents in the same direction ?
(A) Every conductors will experience a force. (B) The two conductors will repel each other.
(C) Each of the conductors will move if not prevented from doing so. (D) none of these
5. Which of the following determine the direction of magnetic field due to a current carrying conductor ?
(A) Faraday’s laws of electromagnetic induction. (B) Fleming’s left-hand rule.
(C) Lenz’s law. (D) Maxwell’s cork screw rule. (E) none of these.
6. If the cylindrical bar magnet is kept along axis and rotated about its axis, then :
(A) a current will be induced in the coil (B) no current will be induced in the coil. (C) only emf will be induced in the coil (D) am emf and current both will be induced in the coil (E) none of these
7. In the figure QR is a vertical conductor and the current I flows from R to Q. P is a point on the horizontal plane and is to the south of the wire. The direction of the magnetic field at P due to the current will be towards :
(A) upward (B) north (C) east (D) west (E) none of these
8. A length of wire carries steady current. It bent first to form a circular plane coil of one turn. The same length is now bent to give a double loop of smaller radius. The magnetic field produced at the centre by the same current will be :
(A) a quarter of its first value (B) a half of first value (C) four times its first value (D) unaltered (E) none of these
9. The intensity of a magnetic field is defined as the force experienced by a :
(A) standard compass (B) unit positive charge
(C) unit negative charge (D) unit north pole
10.. A wire carrying a current of 5A is placed perpendicular to a magnetic induction of 2T. The force on each centimeter of the wire is :
(A) 1N (B) 100 (C) 0.1 N (D) 10 N
11. If a soft iron piece is buried under the surface of earth in the north and south direction, then
(A) it will acquire the properties of a magnet (B) its properties will not change
(C) it will behave like an insulator (D) can’t say with surity
12. Force acting on a stationary charge Q in the magnetic field B is -
(A) B Q V (B) BV/Q (C) Zero (D) BQ/V
13. The permanent magnets are kept with soft iron pieces at ends and keepers :
(A) to magnetise the soft iron pieces (B) to increase the strength of the magnets
(C) to avoid self demagnetisation (D) for physical safety of the magnets
(A) electric motor (B) dynamo (C) transformer (D) battery
15. In case of a DC generator a large number of coils each having many turns and arranged in different turns are used :
(A) to get high voltage DC (B) to get high ampere DC
(C) to get smooth DC (D) get pulsating current
16. Lenz’s law is a consequence of the law of conservations of :
(A) energy (B) momentum (C) angular momentum (D) charge and mass
17. In a DC generator, the induced e.m.f. in the armature is :
(A) DC (B) AC` (D) fluctuating DC (D) both AC and DC
18. The induced emf produced when a magnet is inserted into a coil does not depend upon :
(A) the number of turns in the coil (B) the magnetic moment of the magnet
(C) the magnetic moment of the magnet (D) all of these (E) none of these
19. When the current through a solenoid increases at a constant rate, the induced current :
(A) is a constant and in the direction of inducing current
(B) is a constant and is opposite to the direction of inducing current
(C) increases with time and is in the direction of inducing current
(D) increases with time and opposite to the direction of inducing current
20. The device whish is used for converting electrical energy into mechanical energy is called :
(A) electric (B) dynamo (C) transformer (D) battery
21.The current in the armature of a dc motor is maximum when :
(A) the motor achieves maximum speed (B) the motor achieves intermediate speed
(C) the motor is switched on (D) the motor is switched off
22. The effect of using split rings in a simple DC motor is that :
(A) the direction of rotation of the coil is reversed
(B) the current in the coil always flows in the same direction
(C) the direction of the current flowing in the coil is reversed
(D) None of these
No answer is available for Mcqs. Then only it will helpful.
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