مقناطیسی میدان اور امالہ

Written by Dr. Hamza Farooq (Physics)

نیٹ · طبیعیات · 5 سوالات

نام: ____________________ تاریخ: ____________

Two long parallel wires carry current in the same direction. The force between them is:
- A Repulsive
- B Alternating
- C Attractive
- D Zero
What is the magnetic field 0.1 m from a long straight wire carrying 5 A? (μ₀ = 4 pi x 10⁻⁷ T m/A)
- A 2 x 10⁻⁶ T
- B 5 x 10⁻⁵ T
- C 1 x 10⁻⁵ T
- D 1 x 10⁻⁷ T
What is the magnetic field inside a long solenoid with 1000 turns per metre carrying 2 A? (μ₀ = 4 pi x 10⁻⁷ T m/A)
- A 2.5 x 10⁻³ T
- B 0.25 T
- C 2.5 x 10⁻⁵ T
- D 8 x 10⁻⁴ T
A magnetic field of 0.2 T is perpendicular to a loop of area 0.5 m². What is the magnetic flux through the loop?
- A 0.1 Wb
- B 2.5 Wb
- C 0.7 Wb
- D 0.4 Wb
A 0.2 m rod moves at 10 m/s at right angles to a magnetic field of 0.5 T. What emf is induced across it?
- A 1 V
- B 10 V
- C 0.5 V
- D 0.1 V

جوابی کلید

1. C, 2. C, 3. A, 4. A, 5. A

Parallel currents in the same direction attract each other. Opposite currents repel.
B = μ₀ I / (2 pi r) = 2 x 10⁻⁷ x 5 / 0.1 = 1 x 10⁻⁵ T.
B = μ₀ n I = 4 pi x 10⁻⁷ x 1000 x 2, which is about 2.5 x 10⁻³ T.
Flux = B x A = 0.2 x 0.5 = 0.1 Wb.
Motional emf = B L v = 0.5 x 0.2 x 10 = 1 V.