Asquare loop of wire is carrying current in the counterclockwise direction. there is a horizontal uniform magnetic field pointing to the right. question 1: what is the direction of the net force on the loop? (a) out of the screen(b) into the screen(c) the net force on the loop is zeroquestion 2: in which direction will the loop rotate? (assume the z axis is out of the screen)(a) around the x axis(b) around the y axis(c) around the z axis(d) it will not rotate

1. C) The net force on the loop is zero

Explanation:

The uniform magnetic field points to the right, while the current is counterclockwise. We must analyze the direction of the force on each side of the loop.

However, we notice that:

- the current in the upper and lower side of the loop is parallel/anti-parallel to the magnetic field, so the magnetic force on these sides is zero

- the current in the left side and right side of the loop is perpendicular to the magnetic field, however the direction of the current in the two sides is opposite, so the two forces will be opposite, and since their magnitude is equal (because the field is uniform), then the net force must be zero

2. (B) around the y axis

Explanation:

We already said that the magnetic force on the upper and lower side of the loop is zero. So let's analyze the direction of the force on the left and right side of the loop:

- Left side: the current is flowing downward, while the magnetic field points to the right. Using the right-hand rule:

-- Index finger: current (downward)

-- Middle finger: magnetic field (to the right)

-- Thumb: force (out of the screen, positive z-axis)

- Right side: the current is flowing upward, while the magnetic field points to the right. Using the right-hand rule:

-- Index finger: current (upward)

-- Middle finger: magnetic field (to the right)

-- Thumb: force (into the screen, negative z-axis)

---> this means that the loop of wire will rotate around the y-axis.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.