Explanation:
It is given that,
Diameter of loop, d = 1.4 cm
Radius of loop, r = 0.7 cm = 0.007 m
Magnetic field, 
(A) Magnetic field of a current loop is given by :

I is the current in the loop


I = 27.85 A
(B) Magnetic field at a distance r from a wire is given by :



r = 0.00222 m

Hence, this is the required solution.
Answer:
Mutual inductance, 
Explanation:
(a) A toroidal solenoid with mean radius r and cross-sectional area A is wound uniformly with N₁ turns. A second thyroidal solenoid with N₂ turns is wound uniformly on top of the first, so that the two solenoids have the same cross-sectional area and mean radius.
Mutual inductance is given by :

(b) It is given that,


Radius, r = 10.6 cm = 0.106 m
Area of toroid, 
Mutual inductance, 

or

So, the value of mutual inductance of the toroidal solenoid is
. Hence, this is the required solution.
Answer:
a) 
b) 
c) 
d)
would be the same.
would decrease.
would be the same.
Explanation:
a) On an inclined plane the force of gravity is the sine component of the weight of the block.

b) The friction force is equal to the normal force times coefficient of friction.

c) The work done by the normal force is zero, since there is no motion in the direction of the normal force.
d) The relation between the vertical height and the distance on the ramp is

According to this relation, the work done by the gravity wouldn't change, since the force of gravity includes a term of
.
The work done by the friction force would decrease, because both the cosine term and the distance on the ramp would decline.
The work done by the normal force would still be zero.
Depending on which type of motor you're talking about, but the first 3 are true. A stronger magnetic field in a DC motor will slow it down but increase its torque.
The amount of current in the motor will control the magnetic fields and therefore affect the speed (and torque). In an induction motor, the rotational speed is given by

where f is the line frequency and p is the number of poles. Thus fewer poles makes it go faster.
Answer:
she will eventually slow down and come to a stop