Answer:
the question is incomplete, the complete question is
"A circular coil of radius r = 5 cm and resistance R = 0.2 ? is placed in a uniform magnetic field perpendicular to the plane of the coil. The magnitude of the field changes with time according to B = 0.5 e^-t T. What is the magnitude of the current induced in the coil at the time t = 2 s?"
2.6mA
Explanation:
we need to determine the emf induced in the coil and y applying ohm's law we determine the current induced.
using the formula be low,
where B is the magnitude of the field and A is the area of the circular coil.
First, let determine the area using 
where r is the radius of 5cm or 0.05m
since we no that the angle is at 
we determine the magnitude of the magnetic filed
the Magnitude of the voltage is 0.000532V
Next we determine the current using ohm's law
Answer:
a and b
Explanation:
Hydro static equilibrium holds a star steady and balanced. Whenever a star stops burning hydrogen in its center, there must be evolutionary improvements to maintain equilibrium for the star Of example, if a star's internal pressure and temperature fall, gravity will take over and force the star to contract and heat up, restoring stability. By contrast, if a star's internal pressure and temperature rises, the extra pressure causes the star to widen and cool, restoring balance.
so, according to above explanation options a and b both are true
a) A small increase in the star's internal pressure and temperature causes the star's outer layers to expand and cool.
b) A small decrease in the star's internal pressure and temperature causes the star's outer layers to contract and heat up.
<em>Answer</em>
0.6 teslas
<em>Explanation</em>
When a conductor is inside a magnetic field it experiences a force given by;
Force = ILBsinθ
Where I⇒ current
L ⇒length of the conductor
B ⇒ magnetic field strength
θ ⇒ Angle between the conductor and magnetic field.
F = ILBsinθ
When θ = 90°, Then sin 90 =1 and the formula becomes;
F =ILB
3 = 10 × 0.5 × B
3 = 5B
B = 3/5
= 0.6
magnetic field strength = 0.6 teslas
Answer: C. A rubber eraser
