Answer:9.34 A/s
Explanation:
Given
radius of solenoid 
Emf induced 
no of turns per meter n=450
we know Induced EMF is given by

Magnetic Field is given by

thus 
Area of cross-section
where
solving integration we get

where r=distance from axis
R=radius of Solenoid



A, hope this helped! I didn’t really get it but I think it’s correct?
Answer:
option C
Explanation:
the ball is moving circular around the pole
Angular momentum of the system is constant
J = I ω
now,



the rope radius is decreasing as it revolving around the pole
angular speed is inversely proportional to radius.
so, the angular speed will increase.
The correct answer is option C
Because you are moving down to up
Answer:
With a slower speed-perhaps 5 cm/s answer is c