A 2 cm long copper wire having mass of 6 gm, dips in to two mercury pools to form a complete circuit. The wire is placed between the poles of a magnet which causes a field strength of 0.3 T. Find the initial upward acceleration of copper wire after 100 A of current is passed through the wire (g = 10 m/s2)a)1 m/s2b)10 m/s2c)100 m/s2d)90 m/s2Correct answer is option 'D'. Can you explain this answer?

Question

Answer

ma=Bil−mg
a=0.3×100×2×10⁻²−10×6×10⁻³/ m
a= 0.6−0.06/6×10⁻³
=100−10
=90ms⁻²

Answer

Answer

Given:
Length of copper wire, l = 2 cm = 0.02 m
Mass of copper wire, m = 6 gm = 0.006 kg
Magnetic field strength, B = 0.3 T
Current passing through the wire, I = 100 A
Acceleration due to gravity, g = 10 m/s^2

To find:
Initial upward acceleration of copper wire

Solution:
1. Magnetic force on the wire:
Magnetic force on the wire is given by the formula:
F = BIL sinθ
where, B = magnetic field strength, I = current passing through the wire, L = length of the wire in the magnetic field, and θ = angle between the magnetic field and the wire.

Here, the wire is placed between the poles of a magnet, which causes a magnetic field perpendicular to the wire. So, the angle between the magnetic field and the wire is 90 degrees, i.e., sinθ = 1.

So, the magnetic force on the wire is:
F = BIL

Substituting the given values, we get:
F = 0.3 x 100 x 0.02
F = 0.6 N

2. Weight of the wire:
Weight of the wire is given by the formula:
W = mg
where, m = mass of the wire, and g = acceleration due to gravity.

Substituting the given values, we get:
W = 0.006 x 10
W = 0.06 N

3. Net upward force on the wire:
Net upward force on the wire is given by the formula:
Fnet = F - W

Substituting the calculated values, we get:
Fnet = 0.6 - 0.06
Fnet = 0.54 N

4. Upward acceleration of the wire:
Upward acceleration of the wire is given by the formula:
a = Fnet/m

Substituting the calculated values, we get:
a = 0.54/0.006
a = 90 m/s^2

Therefore, the initial upward acceleration of the copper wire after 100 A of current is passed through the wire is 90 m/s^2, which is option D.

Answer

Plzzz explain this one...

Answer

I got the answer 90, but I can't attach image due to servor problem
use F=BIL and a=F/m

Answer

D

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