Answer:
Explanation:
The area of a circle is given b
A=πr²
Then,
dA/dr= 2πr
Also give that,
dr/dt=30m/hr, r=100m
We want to find dA/dt
dA/dt=dA/dr×dr/dt
dA/dt= 2πr × 30
dA/dt= 2 ×π ×100×30
dA/dt=18849.56m²/s.
The rate of the area is 18849.56m²/s
Answer:
option (D
Explanation:
Torque is given by
torque = N x i x A x B x sinФ
where, N is number of turns, A is area, b is the magnetic field and Ф be the angle between the area vector and the magnetic field vector, i be the current.
So, torque depends on the current.
option (D)
An alloy that contains mainly copper and tin is bronze
