Answer:
A. Zero
Explanation:
The force on a coil of N turns, enclosing an area, A and carrying a current I in the presence of a magnetic field B, is :
F = N * I * A * B * sinθ
Where θ is the angle between the normal of the enclosed area and the magnetic field.
Since the normal of the area is parallel to the magnetic field, θ = 0
Hence:
F = NIABsin0
F = 0 or Zero
D
Because if an object is moving at a constant speed the force of friction must equal the applied (horizontal) force, and for it to be accelerating or decelerating, the force of friction and the applied force must be unequal
Answer: It has a range of visible and invisible forms of radiation.
Explanation:
Electromagnetic wave is defined as the wave which is associated with both electrical and magnetic component associated with them. They can travel in vacuum as well and travel with the speed of light i.e 
The electromagnetic radiations consist of radio waves, microwaves, infrared ,Visible , ultraviolet, X rays and gamma rays arranged in order of increasing frequency and decreasing wavelengths.
Only visible light is visible to naked eyes.
The relationship between wavelength and frequency of the wave follows the equation:

where,
= frequency of the wave
c = speed of light
= wavelength of the wave
From the above relation, it is visible that wavelength and frequency follow inverse relation. For increase in wavelength, the value of frequency decreases and vice-versa.