Class 10 Science (NCERT)

1. Who first discovered the magnetic effect of electric current in 1820?

• A. Michael Faraday
• B. Hans Christian Oersted
• C. James Clerk Maxwell
• D. André-Marie Ampère

2. Magnetic field lines emerge from which pole and enter at which pole outside a bar magnet?

• A. Emerge from South Pole, enter at North Pole
• B. Emerge from North Pole, enter at South Pole
• C. Emerge from Center, enter at Poles
• D. Emerge from East Pole, enter at West Pole

3. Inside a bar magnet, the direction of magnetic field lines is from:

• A. North Pole to South Pole
• B. South Pole to North Pole
• C. Center to edges
• D. Top to bottom

4. The degree of closeness of magnetic field lines indicates the:

• A. Direction of magnetic field
• B. Temperature of magnet
• C. Relative strength of the magnetic field
• D. Speed of electric current

5. Why do two magnetic field lines never intersect each other?

• A. Because magnetic forces cancel out
• B. Because at the point of intersection, a compass needle would point in two directions simultaneously, which is impossible
• C. Because field lines are straight parallel lines
• D. Because magnetic field is a scalar quantity

6. The shape of magnetic field lines around a straight current-carrying conductor consists of:

• A. Parallel straight lines
• B. Concentric circles
• C. Elliptical loops
• D. Hyperbolic curves

7. Which rule is used to find the direction of magnetic field lines around a straight current-carrying conductor?

• A. Fleming's Left-Hand Rule
• B. Fleming's Right-Hand Rule
• C. Right-Hand Thumb Rule
• D. Ampere's Swimming Rule

8. The magnetic field strength near a current-carrying circular loop increases when:

• A. The current is decreased
• B. The radius of the loop is increased
• C. The number of turns in the coil is increased
• D. The loop is placed in vacuum

9. A long cylindrical coil of many insulated copper wire turns wrapped closely in the shape of a cylinder is called a:

• A. Solenoid
• B. Rheostat
• C. Galvanometer
• D. Commutator

10. The magnetic field inside a long straight current-carrying solenoid is:

• A. Zero
• B. Uniform (same at all points)
• C. Decreases towards the center
• D. Different at every point

11. A soft iron core placed inside a current-carrying solenoid forms a temporary magnet known as an:

• A. Permanent magnet
• B. Electromagnet
• C. Bar magnet
• D. Isotope

12. The magnitude of force experienced by a current-carrying conductor in a magnetic field is maximum when the angle between conductor and field is:

• A. 0°
• B. 45°
• C. 90°
• D. 180°

13. Which rule gives the direction of mechanical force acting on a current-carrying conductor in a magnetic field?

• A. Fleming's Left-Hand Rule
• B. Fleming's Right-Hand Rule
• C. Right-Hand Thumb Rule
• D. Maxwell's Corkscrew Rule

14. In Fleming's Left-Hand Rule, the forefinger points in the direction of the:

• A. Electric Current
• B. Motion of conductor
• C. Magnetic Field
• D. Induced Current

15. An electron enters a magnetic field at right angles to it. The direction of force acting on the electron will be:

• A. In direction of motion of electron
• B. Opposite to motion of electron
• C. Into the page / perpendicular to both field and conventional current
• D. Out of the page

16. The SI unit of magnetic field strength (magnetic flux density) is:

• A. Weber
• B. Tesla (T)
• C. Henry
• D. Gauss

17. In domestic electric circuits, the live wire is usually covered with insulation of color:

• A. Green
• B. Black
• C. Red or Brown
• D. Yellow

18. In India, the potential difference between live wire and neutral wire in domestic AC supply is:

• A. 110 V
• B. 220 V
• C. 440 V
• D. 12 V

19. What is the frequency of alternating current (AC) supplied for domestic use in India?

• A. 60 Hz
• B. 50 Hz
• C. 100 Hz
• D. 0 Hz

20. Earth wire is connected to metallic bodies of high power appliances to prevent:

• A. Overheating of wires
• B. Severe electric shock due to current leakage
• C. Short circuiting
• D. High energy consumption

21. A condition when live wire and neutral wire come in direct contact with each other due to damaged insulation is called:

• A. Overloading
• B. Earthing
• C. Short Circuiting
• D. Electromagnetic Induction

22. Connecting too many heavy electrical appliances to a single socket simultaneously causes:

• A. Short circuit
• B. Overloading
• C. Induction
• D. High voltage

23. An electric fuse wire must possess:

• A. High resistance and high melting point
• B. Low resistance and low melting point
• C. High resistance and low melting point
• D. Low resistance and high melting point

24. What happens to the force on a current-carrying wire in a magnetic field if the magnetic field strength is doubled?

• A. Force is halved
• B. Force remains unchanged
• C. Force is doubled
• D. Force becomes quadrupled

25. A current flowing vertically downwards in a straight conductor produces a magnetic field around it in which direction (seen from above)?

• A. Clockwise
• B. Anti-clockwise
• C. Upward
• D. Downward

26. 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

27. Which of the following material cannot be magnetized easily to make a permanent magnet?

• A. Steel
• B. Alnico
• C. Soft Iron
• D. Nipermag

28. The magnetic field at the center of a circular current-carrying coil is:

• A. Circular
• B. Straight parallel lines perpendicular to the plane of loop
• C. Zero
• D. Elliptical

29. An electric fuse works on which effect of electric current?

• A. Magnetic effect
• B. Chemical effect
• C. Heating effect
• D. Optical effect

30. Commercial electric motors do not use:

• A. An electromagnet to rotate the armature
• B. Effectively large number of turns of conducting wire
• C. Permanent magnets to rotate the armature
• D. A soft iron core on which coil is wound