Answer: The correct option is Option b.
Explanation:
Power is defined as the rate of work done by an object.
Mathematically,
.....(1)
And work done is the product of force exerted on the object times the displacement covered by that object.
Mathematically,

Putting this value in above equation, we get:

where,
P = power = ?W
F = Force exerted = 10N
s = Displacement = 400cm = 4m (Conversion factor: 1m = 100 cm)
t = Time taken = 8s
Putting values in above equation, we get

Hence, the correct option is Option b.
Answer:
The magnitude of the magnetic force on the rod is 0.037 N.
Explanation:
The magnetic force is given by:

Since the charge (q) is:
Where<em> I</em> is the current = 1.40 A, and <em>t</em> the time
And the speed (v):
Where <em>L </em>is the tracks separation = 2.20 cm = 0.022 m
Hence, the magnetic force is:

Where <em>B </em>is the magnetic field = 1.20 T and <em>θ</em> is the angle between the tracks and the magnetic field = 90°

Therefore, the magnitude of the magnetic force on the rod is 0.037 N.
I hope it helps you!
Answer:C
Explanation:
Mass energy of hydrogen fusing into helium
Explanation:
The kinetic energy of a moving object is directly proportional to its mass and directly proportional to the square of its velocity. This means that an object with twice the mass and equal speed will have twice the kinetic energy while an object with equal mass and twice the speed will have quadruple the kinetic energy.