  # Important Questions for CBSE Class 10 Science Chapter 13 - Magnetic Effects of Electric Current 1 Mark Question

## CBSE Class 10 Science Chapter-13 Magnetic Effects of Electric Current – Free PDF Download

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CBSE Class 10 Science Chapter-13 Magnetic Effects of Electric Current Important Questions

## 1 Mark Questions

1. Magnetic field lines determine
(a) The shape of magnetic field
(b) Only the direction of magnetic field
(c) Only the relative strength of the magnetic field
(d) Both the direction and the relative strength of magnetic field
Ans. (d) Both the direction and the relative strength of magnetic field

2. A device for producing electric current is called a
(a) Galvanometer
(b) Motor
(c) Generator
(d)Ammeter
Ans. (c) Generator

3. At the time of short circuit, the current in the circuit
(a) vary continuously
(b) reduced considerably
(c) increases heavily
(d) does not change
Ans. (c) increases heavily

4. Figure shows the magnetic field lines between the two faces A and B of two magnets. (a) Both faces A and B of two bar magnets are North pole.

(b) Both faces A and B of two bar magnets are South pole.
(c) Face A is south pole while face B is north pole.
(d) None of the above.
Ans. (d) None of the above.

5. The magnetic field near a long straight wire is described by
(a) Straight field lines parallel to the wire.
(b) Straight field lines perpendicular to the wire.
(c) Connective circle centered on the wire.
(d) Radial field lines starting from the wire.
Ans. (c) Connective circle centered on the wire.

6. A current carrying conductor placed in magnetic field experiences a force. The displacement of the conductor in magnetic field can be increased by
(a)Decreasing the magnetic field.
(b) Decreasing the current in the conductor.
(c) Increasing the magnetic field.
(d) None of the above.
Ans. (c) Increasing the magnetic field.

7. A positively charged particle say an alpha particle projected towards west is deflected toward north by a magnetic field. The direction of the magnetic field is
(a) Upward
(b) downward
(c) towards south
(d) towards east.
Ans. (d) towards east.

8. Which of the following properties of a proton can change when it moves freely in a magnetic field
(a) mass
(b) speed
(c) velocity
(d) momentum
Ans. (c) velocity

9. The direction of the magnetic field at a point P above the wire carrying current as shown in the figure is (a) Down the page

(b) up the page
(c) into the page
(d) out of the page
Ans. (c) velocity

10. Concentric circles with arrows centered at the wire AB are shown in figure. (a) No current in AB

(b) current flows from B to A
(c) current – flows from A to B
(d) none of these
Ans. (b) current flows from B to A

11. Electric motor converts
(a) Mechanical energy into electrical energy
(b) Mechanical energy into heat energy
(c) Electrical energy into heat energy
(d) Electrical energy into mechanical energy
Ans. (d) Electrical energy into mechanical energy

12. Potential difference between a live wire and a neutral wire is
(a) 200 volt
(b) 150 volt
(c) 210 volt
(d) 220 volt
Ans. (d) 220 volt.

13. The most important safety device method used for protecting electrical appliances from short circuiting or overloading is
(a) Earthing
(b) use of stabilizer
(c) use of electric meter
(d) fuse
Ans. (d) fuse

14. Forces acting on a stationery charge of in the magnetic field B is
(a) BQ v
(b) BQ/v
(c) Bv/Q
(d) zero
Ans. (d) zero

15. The rectangular coil of copper wires is rotated in a magnetic field. The direction of induced current change once in each
(a) one revolution
(b) one fourth revolution
(c) half revolution
(d) two revolutions
Ans. (b) one fourth revolution

16. Choose the correct option:
(a) The magnetic field inside a long straight solenoid-carrying current Is zero.
(b)Decrease as we move towards its end.
(c)Increase as we move towards it end.
(d)Is the same all points.
Ans. (d) is the same at all points.

17. Which of the following property of a proton can change while it moves freely in a magnetic field?
(a) mass
(b) speed
(c) velocity
(d) momentum
Ans. (c), (d) Velocity as well as momentum will change.

18. A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is:
(a) towards south
(b)towards east
(c) downward
(d) upward
Ans. (d) the direction of magnetic field is vertically upward.

19. Name some sources of direct current.
Ans. Some sources of direct current are a cell, a battery and a D.C. generator.

20. Choose the correct option:
A rectangular coil of copper wires is rotated in a magnetic filed. The direction of the induced current changes once in each
(a) two revolutions
(b) one revolution
(c) half revolution
(d) one-fourth revolution
Ans. (c) half-rotation.

21. Which one of the following correctly describes the magnetic field near a long straight wire?
(a) The field consists of straight lines perpendicular to the wire.
(b) The field consists of straight lines parallel to the wire
(c) The field consists of radial lines originating from the wire
(d) The field consists of concentric circles centered on the wire
Ans. (d) The field consists of concentric circles centered on the wire.

22.The phenomenon of electromagnetic induction is
(a) the process of charging a body.
(b) the process of generating magnetic field due to a current passing through a coil.
(c) producing induced current in a coil due to relative motion between a magnet and the coil.
(d) the process of rotating a coil at an electric motor.
Ans. (c) producing induced current in a coil due to relative motion between a magnet and the coil.

23. The device used for producing electric current is called
(a) generator
(b) galvanometer
(c) ammeter
(d) motor
Ans. (a) generator

24.The essential difference between A.C. generator and a D.C. generator is that
(a) A.C. generator has an electromagnet while a D.C. generator has permanent magnet.
(b) D.C. generator will generate a higher voltage
(c) A.C. generator will generate a higher voltage
(d) A.C. generator has slip rings while the D.C. generator has commentator.
Ans. (d) A.C. generator has slip rings while the D.C. generator has commentator.

25. At the time of short circuit, the current in the circuit:
(a) reduce substantially
(b) does not change
(c) increase heavily
(d) vary continuously
Ans. (c) increase heavily

26. In which position the force on conductor is maximum when it uniform magnetic field? is placed in
Ans. When conductor is Perpendicular to field

27. How can it be shown that magnetic field exist around a wire carrying current?
Ans. By using magnetic compass which, shows deflection.

28. How can a solenoid be used to magnet a steel bar.
Ans. By inserting the steel bar inside the solenoid and switching on electric current.

29. Why can’t two magnetic field lines ever intersect?
Ans. If so then at the point of intersection there will be two different directions of magnetic field which is not possible.

30. Can 5A fuse be used in wire carrying 15 A current? Why?
Ans. because both of them would then be ineffective in controlling the amount of current flowing.

31. Give the factors that affect strength of magnetic field at a point due to a straight conductor carrying current.
Ans. Magnitude of electric content, perpendicular distance between that point and conductor.

32. Where do we connect a fuse: with live wire or with neutral wire?
Ans. It is always connected with live wire.

33. Name any two devices which use permanent magnets.
Ans. Loudspeakers, (Galvanometer, voltmeter).

34. Draw the magnetic field lines representing uniform magnetic field.
Ans. 35. If the frequency of A.C. is 50 Hz. Then how many times it is changing its direction in 1 second?
Ans. 100 Times.

36. What is the pattern of the magnetic field lines around a straight conductor carrying current?
Ans. Concentric circles

37. If the current is flowing in the direction of advancement of screw, then what is the direction of magnetic field lines?
Ans. In the direction of rotation or screw.

38. How can you say that the magnetic field is uniform inside the solenoid.
Ans. Because field lines are parallel inside the solenoid.

39. Which property of a proton will change while it moves freely in a magnetic field?
Ans. Momentum or Velocity.

40. According to Flemings right hand rule, which part of right hand indicate the movement of conductor?
Ans. Thumb

41. If the no. of turns of a circular current carrying coil are doubled, then how will the magnetic field produced by it changes?
Ans. Doubled