NEET2026PhysicsChapterActual
A metallic rectangular frame of dimensions 25 cm 10 cm is pushed into a region of uniform magnetic field of 0.8 T directed perpendicular to the plane of the frame. The frame moves with a constant speed of 2 cm s ⁻¹ . If the direction of motion is parallel to the longer side of the frame, what is the magnitude of the motional emf induced in the frame?
Options
- A4.0 10⁻³ V
- B1.6 10⁻⁴ V
- C1.6 10⁻³ V
- D4.0 10⁻⁴ V
Correct answer
C. 1.6 10⁻³ V
Step-by-step solution
Motional emf induced in a conductor of length l moving with velocity v perpendicular to a magnetic field B is given by E = Blv . Since the frame moves parallel to its longer side, the side perpendicular to the direction of motion is the shorter side. Thus, the effective length l cutting the magnetic field lines is 10 cm . Given: B = 0.8 T l = 10 cm = 0.1 m v = 2 cm s ⁻¹ = 0.02 m s ⁻¹ Substituting the values: E = 0.8 0.1 0.02 E = 1.6 10⁻³ V Answer: 1.6 10⁻³ V