The answer is C voltmeter
Answer:
6.03 mV
Explanation:
length of solenoid, L = 2 m, N = 12000, di/dt = 40 A/s,
Magnetic field due to solenoid
B = μ0 n i = μ0 N i / L
dB/dt = μ0 N / L x di / dt
dB /dt = (4 x 3.14 x 10^-7 x 12000 x 40) / 2 = 0.3 T/s
Induced emf, e = rate of change of magnetic flux
e = dΦ / dt = A x dB / dt
e = 3.14 x 0.08 x 0.08 x 0.3 = 6.03 x 10^-3 V = 6.03 mV
Density =mass/volume 120/200 =0.6 g/cm
The Correct choice is ~
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Magma is a molten and semi-molten rock mixture found under the surface of the earth. and i think silica is the most abundant. hope it helps.sorry if it's uncorrect. :)
