Q45.Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : A electron in a certain region of uniform magnetic field is moving with constant velocity in a straight line path. Reason (R): The magnetic field in that region is along the direction of velocity of the electron. In the light of the above statements, choose the correct answer from the options given below : (1) (A) is true but (R) is false (2) Both (A) and (R) are true but (R) is NOT the correct explanation of (A) (3) Both (A) and (R) are true and (R) is the correct (4) (A) is false but (R) is true explanation of (A)
What This Question Tests
This question assesses the knowledge of the Lorentz force and the conditions under which a charged particle can move with constant velocity in a uniform magnetic field.
Concepts Tested
Formulas Used
F = q(v x B)
📚 NCERT Sections This Tests
4.11 — In A Chamber, A Uniform Magnetic Field Of 6.5 G (1 G = 10–4 T) Is
Physics Class 11 · Chapter 4
4.11 In a chamber, a uniform magnetic field of 6.5 G (1 G = 10–4 T) is maintained. An electron is shot into the field with a speed of 4.8 × 106 m s–1 normal to the field. Explain why the path of the electron is a circle. Determine the radius of the circular orbit. (e = 1.5 × 10–19 C, me = 9.1×10–31 kg)
4.4 — A Horizontal Overhead Power Line Carries A Current Of 90 A In East To
Physics Class 11 · Chapter 4
4.4 A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?
4.5 — What Is The Magnitude Of Magnetic Force Per Unit Length On A Wire
Physics Class 11 · Chapter 4
4.5 What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle of 30º with the direction of a uniform magnetic field of 0.15 T?
📋 Question Details
- Chapter
- Magnetic Effects of Current
- Topic
- Magnetic force on a moving charge
- Year
- 2025
- Shift
- 24 Jan Shift 2
- Q Number
- Q45
- Type
- Assertion Reasoning
- NCERT Ref
- Class 12 Physics Ch 4: Magnetic Effects of Current
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