Answer:
7.1 Hz
Explanation:
In a generator, the maximum induced emf is given by

where
N is the number of turns in the coil
A is the area of the coil
B is the magnetic field strength
f is the frequency
In this problem, we have
N = 200


B = 0.030 T
So we can re-arrange the equation to find the frequency of the generator:

B
Djdjsjdnkajdnsbsjsixhsjbsjsisahjsbxjsjsndnxnsjdd
Answer:
a

b

Explanation:
From the question we are told that
The mass of the rock is 
The length of the small object from the rock is 
The length of the small object from the branch 
An image representing this lever set-up is shown on the first uploaded image
Here the small object acts as a fulcrum
The force exerted by the weight of the rock is mathematically evaluated as

substituting values


So at equilibrium the sum of the moment about the fulcrum is mathematically represented as

Here
is very small so
and 
Hence

=> 
substituting values


The mechanical advantage is mathematically evaluated as

substituting values


From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is

Here,
f = Focal Length
R = Radius
Rearranging to find the radius we have,

Replacing with our values,
R = 2(13.8cm)
R = 27.6cm
Therefore the radius of the spherical surface from which the mirror was made is 27.6cm
Answer:
0.855 N
Explanation:
Using
F = BILsinФ.................... Equation 1
Where F = magnitude of the force exerted on the wire, B = magnetic Field, I = current, L = Length of the wire in the magnetic Field, Ф = angle between the wire and the magnetic field.
Given: B = 0.95 T, I = 15.0 A, L = 2r, r = radius = 3.0 cm = 0.03 m L = 2×0.03 = 0.06 m, Ф = 90° (perpendicular)
Substitute into equation 1
F = 0.95(15)(0.06)sin90°
F = 0.855 N.
Hence the magnitude of force that is exerted on the wire = 0.855 N