Magnetic Effects of Current – CBSE Class 10
1. A current-carrying conductor produces
A) Magnetic field around it
B) Heat only
C) Light
D) Chemical effect
Answer: Magnetic field around it
2. The magnetic field around a straight conductor is
A) Circular and concentric
B) Linear
C) Elliptical
D) Random
Answer: Circular and concentric
3. Right-hand thumb rule is used to find
A) Direction of magnetic field around straight conductor
B) Direction of current
C) Direction of force
D) Voltage
Answer: Direction of magnetic field around straight conductor
4. Fleming’s left-hand rule is used to find
A) Direction of force on a current-carrying conductor in magnetic field
B) Direction of current
C) Direction of magnetic field
D) Voltage
Answer: Direction of force on a current-carrying conductor in magnetic field
5. A solenoid is a
A) Coil of wire producing nearly uniform magnetic field inside
B) Single straight conductor
C) Permanent magnet
D) Copper rod
Answer: Coil of wire producing nearly uniform magnetic field inside
6. Magnetic field inside a current-carrying solenoid is
A) Nearly uniform
B) Non-uniform
C) Zero
D) Circular only
Answer: Nearly uniform
7. Magnetic field lines inside a solenoid are
A) Parallel
B) Circular
C) Elliptical
D) Random
Answer: Parallel
Magnetic Effects of Current – CBSE Class 10
8. An electromagnet is made by
A) Winding wire around soft iron core and passing current
B) Using permanent magnet
C) Using copper plate
D) Using battery only
Answer: Winding wire around soft iron core and passing current
9. Magnetic field of a solenoid can be increased by
A) Increasing current
B) Increasing number of turns
C) Using soft iron core
D) All of these
Answer: All of these
10. Electromagnets are used in
A) Electric bells
B) Magnetic cranes
C) Relay switches
D) All of these
Answer: All of these
11. Poles of an electromagnet can be reversed by
A) Reversing current direction
B) Changing core material
C) Changing solenoid length
D) None
Answer: Reversing current direction
12. Magnetic field lines of a current-carrying loop are
A) Similar to bar magnet field lines
B) Circular around wire only
C) Random
D) Elliptical
Answer: Similar to bar magnet field lines
13. Right-hand grip rule helps in
A) Determining direction of field lines around solenoid
B) Force direction
C) Current
D) Voltage
Answer: Determining direction of field lines around solenoid
14. Current in a conductor produces
A) Magnetic effect
B) Heating effect
C) Both A and B
D) None
Answer: Both A and B
15. Magnetic effect of current is utilized in
A) Electric bell
B) Electromagnet
C) Electric motor
D) All of these
Answer: All of these
16. When current passes through solenoid, it behaves like
A) Bar magnet
B) Coil only
C) Wire
D) None
Answer: Bar magnet
17. Magnetic field of a long straight wire at distance r is
A) B = μ₀I/2πr
B) B = μ₀I/r²
C) B = μ₀I/πr
D) B = μ₀Ir
Answer: B = μ₀I/2πr
18. Magnetic field inside solenoid is given by
A) B = μ₀nI
B) B = μ₀I/2πr
C) B = I²R
D) B = VI
Answer: B = μ₀nI
19. Earth’s magnetic field is
A) Weak, about 0.5 gauss
B) Strong, 100 gauss
C) Zero
D) None
Answer: Weak, about 0.5 gauss
20. Fleming’s left-hand rule directions are
A) Thumb – Force, Forefinger – Magnetic field, Middle finger – Current
B) Thumb – Current, Forefinger – Force, Middle – Field
C) Thumb – Field, Forefinger – Current, Middle – Force
D) None
Answer: Thumb – Force, Forefinger – Magnetic field, Middle finger – Current
Magnetic Effects of Current – CBSE Class 10
21. Electromagnet loses magnetism when
A) Current is switched off
B) Core is heated
C) Core is removed
D) None
Answer: Current is switched off
22. Permanent magnet is made of
A) Hard magnetic materials
B) Soft magnetic materials
C) Copper
D) Aluminium
Answer: Hard magnetic materials
23. Soft iron is used in electromagnet because
A) Easily magnetized and demagnetized
B) Cheap
C) Conducts electricity
D) None
Answer: Easily magnetized and demagnetized
24. Magnetic field inside coil depends on
A) Number of turns per unit length and current
B) Wire material
C) Core color
D) None
Answer: Number of turns per unit length and current
25. Magnetic field inside solenoid is strongest at
A) Center
B) Ends
C) Outside
D) None
Answer: Center
26. Magnetic field lines outside solenoid
A) Resemble bar magnet
B) Circular
C) Elliptical
D) Random
Answer: Resemble bar magnet
27. Current-carrying circular loop behaves like
A) Magnetic dipole
B) Wire only
C) Coil only
D) None
Answer: Magnetic dipole
28. Magnetic field strength increases when
A) Current increases
B) Number of turns increases
C) Both A and B
D) None
Answer: Both A and B
29. Electromagnet is stronger than permanent magnet because
A) Strength can be controlled
B) Permanent magnet cannot be switched off
C) Both
D) None
Answer: Strength can be controlled
Magnetic Effects of Current – CBSE Class 10
30. Core material of electromagnet is usually
A) Soft iron
B) Copper
C) Aluminium
D) Steel
Answer: Soft iron
31. Magnetic field around straight wire is
A) Concentric circles
B) Parallel lines
C) Bar magnet type
D) Random
Answer: Concentric circles
32. Magnetic field around circular coil resembles
A) Bar magnet
B) Straight wire
C) Solenoid
D) None
Answer: Bar magnet
33. Solenoid is used to make electromagnet because
A) Field inside is strong and uniform
B) Field outside is weak
C) Easy to control
D) All of these
Answer: All of these
34. Magnetic field due to current is proportional to
A) Current
B) Square of current
C) Resistance
D) Voltage
Answer: Current
35. Applications of electromagnet include
A) Electric bells
B) Relays
C) Lifting heavy objects
D) All of these
Answer: All of these
36. Electromagnet can be made stronger by
A) Increasing current
B) Increasing number of turns
C) Using soft iron core
D) All of these
Answer: All of these
37. Solenoid with iron core is called
A) Electromagnet
B) Permanent magnet
C) Bar magnet
D) Wire loop
Answer: Electromagnet
38. Magnetic field lines inside solenoid are
A) Parallel and uniform
B) Circular only
C) Random
D) Elliptical
Answer: Parallel and uniform
39. Magnetic field lines outside solenoid
A) Emerge from North and enter South
B) Circular
C) Random
D) Elliptical
Answer: Emerge from North and enter South
40. Right-hand thumb rule determines
A) Direction of field around straight wire
B) Force
C) Current
D) None
Answer: Direction of field around straight wire
Magnetic Effects of Current – CBSE Class 10
41. Electromagnet loses magnetism when
A) Current is switched off
B) Current increases
C) Core removed
D) Both A and C
Answer: Both A and C
42. Electromagnet is used in lifting heavy metallic objects because
A) Strong and controllable
B) Permanent magnet is weak
C) Cheap
D) None
Answer: Strong and controllable
43. Earth behaves like
A) Giant magnet
B) Electromagnet
C) Solenoid
D) Conductor
Answer: Giant magnet
44. Force on current-carrying wire in magnetic field depends on
A) Current, magnetic field, length of wire, angle
B) Voltage
C) Resistance
D) None
Answer: Current, magnetic field, length of wire, angle
45. Electromagnet is preferred over permanent magnet because
A) Strength can be controlled
B) Polarity can be reversed
C) Both A and B
D) None
Answer: Both A and B
46. Magnetic effect of current was discovered by
A) Oersted
B) Faraday
C) Coulomb
D) Ampere
Answer: Oersted
47. Fleming’s left-hand rule is for
A) Motors
B) Generators
C) Both
D) None
Answer: Motors
48. Electromagnetic crane works on
A) Magnetic effect of current
B) Heating effect
C) Chemical effect
D) None
Answer: Magnetic effect of current
49. Magnetic field inside solenoid is directly proportional to
A) Number of turns per unit length and current
B) Wire thickness
C) Voltage only
D) Resistance
Answer: Number of turns per unit length and current
50. Soft iron core is used in electromagnets because
A) It enhances magnetic field and demagnetizes easily
B) Hard to magnetize
C) Cheap
D) Conducts electricity
Answer: It enhances magnetic field and demagnetizes easily