The coercivity of a small magnet where the ferromagnet gets demagnetised is 3× 103 A m-1 . The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetised when inside the solenoid, is

Question

The coercivity of a small magnet where the ferromagnet gets demagnetised is 3× 103 A m-1 . The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetised when inside the solenoid, is (A) 30 mA (B) 60 mA (C) 3 A (D) 6A

Tardigrade Admin · Accepted Answer

B=μ0 n i (B/μ0)=n i 3 × 103=(N I/L)=(100 × i/10 × 10-2) I=3 A

Q. The coercivity of a small magnet where the ferromagnet gets demagnetised is $3 \times 10^{3} A m^{- 1}$ . The current required to be passed in a solenoid of length $10 c m$ and number of turns $100$ , so that the magnet gets demagnetised when inside the solenoid, is

30 mA

60 mA

3 A

6A

$B = μ_{0} n i$
$\frac{B}{μ _{0}} = ni$
$3 \times 1 0^{3} = \frac{N I}{L} = \frac{100 \times i}{10 \times 1 0 ^{- 2}}$
$I = 3 A$

Q. The coercivity of a small magnet where the ferromagnet gets demagnetised is 3×103Am−1 . The current required to be passed in a solenoid of length 10cm and number of turns 100, so that the magnet gets demagnetised when inside the solenoid, is

30 mA

60 mA

3 A

6A

B=μ0​ni μ0​B​=ni 3×103=LNI​=10×10−2100×i​ I=3A

Q. The coercivity of a small magnet where the ferromagnet gets demagnetised is $3 \times 10^{3} A m^{- 1}$ . The current required to be passed in a solenoid of length $10 c m$ and number of turns $100$ , so that the magnet gets demagnetised when inside the solenoid, is

$B = μ_{0} n i$
$\frac{B}{μ _{0}} = ni$
$3 \times 1 0^{3} = \frac{N I}{L} = \frac{100 \times i}{10 \times 1 0 ^{- 2}}$
$I = 3 A$