Answer:
83.3 Wb
Explanation:
The magnetic flux linkage through the coil is given by:

where
B is the magnetic field strength
A is the cross sectional area
N is the number of turns in the coil
is the angle between the direction of the field and the normal to the coil
In this problem:
B = 1.74 T
A = 0.133 m^2
N = 360

Therefore, the magnetic flux linkage is

Answer:
d) It will be cut to a fourth of the original force.
Explanation:
The magnitude of the electrostatic force between the charged objects is

where
k is the Coulomb's constant
q1 and q2 are the charges of the two objects
r is the separation between the two objects
In this problem, the initial distance is doubled, so
r' = 2r
Therefore, the new electrostatic force will be

So, the force will be cut to 1/4 of the original value.
The density of the object is the ratio of its mass and volume. From the given dimensions above, we determine the volume through the equation,
V = L x W x H
Substituting,
V = (3 cm)(2 cm)(1 cm) = 6 cm³
From the idea presented above,
d = m/V
Substituting the known values,
d = (30 g)/ (6 cm³) = 5 g/cm³
ANSWER: 5 g/cm³