It goes in the downward direction
Complete Question:
A hollow cylinder with an inner radius of 4.0mm and an outer radius of 30mm conducts a 3.0-A current flowing parallel to the axis of the cylinder. If the current density is uniform throughout the wire, what is the magnitude of the magnetic field at a point 12mm from its center?
Answer:
The magnitude of the magnetic field = 7.24 μT
Explanation:
Inner radius, a = 4.0 mm = 0.004 m
Outer radius, b = 30 mm = 0.03 m
Radius, r = 12 mm = 0.012 m
let h² = b² - a²
h² = 0.03² - 0.004²
h² = 0.000884
Let d² = r² - a²
d² = 0.012² - 0.004²
d² = 0.000128
Current I = 3A
μ = 4π * 10⁻⁷
The magnitude of the magnetic field is given by:

B = 7.24 * 10⁻⁶T
B = 7.24 μT
(a) As the car is moving with constant velocity, it means the rate change of velocity does not change, therefore the average acceleration of the car is zero.
Thus, there is no acceleration, when velocity is constant.
(b) Average acceleration,

Here, v is final velocity and u is the initial velocity and
is the time interval.
As twelve seconds later, the car is halfway around the track and traveling in the opposite direction with the same speed, therefore

Thus, the average acceleration of the car is
in the direction to the left.
Answer:
The electric potential difference is 32500 volt.
Explanation:
Given that,
Charge
Energy = 6.5 J
We need to calculate the electric potential difference
Potential difference :
Potential difference is equal to the energy divide by charge.
Using formula of potential difference



Hence, The electric potential difference is 32500 volt.