Answer: The correct answer is Option b. Distance.
Explanation:
Scientists and astronomers use this unit to measure the distance in space. A light year is a unit of distance and not time because light travels very fast and it travels a lot of distance in one year.
Light year is basically defined as how far the beam of light travels in a year.
Therefore, this light year is a unit of distance. Hence, the correct option is option b.

Answer;
the colors of light that plants require for photosynthesis
Explanation;
The color of light used for photosynthesis depends on the pigment in the plant. For example, green plants with chlorophylls and carotenoids have a maximum activity with violet-blue and red light.
White light contains various colors, including red, orange, yellow, green, blue, indigo and violet. When plants harvest light for photosynthesis, they only absorb a few colors and reflect the rest. Plants appear green because chlorophyll absorbs other colors and reflects green.
Answer:
<em>B) 1.0 × 10^5 V</em>
Explanation:
<u>Electric Potential Due To Point Charges
</u>
The electric potential produced from a point charge Q at a distance r from the charge is

The total electric potential for a system of point charges is equal to the sum of their individual potentials. This is a scalar sum, so direction is not relevant.
We must compute the total electric potential in the center of the square. We need to know the distance from all the corners to the center. The diagonal of the square is

where a is the length of the side.
The distance from any corner to the center is half the diagonal, thus


The total potential is

Where V1 and V2 are produced by the +4\mu C charges and V3 and V4 are produced by the two opposite charges of
. Since all the distances are equal, and the charges producing V3 and V4 are opposite, V3 and V4 cancel each other. We only need to compute V1 or V2, since they are equal, but they won't cancel.


The total potential is


Answer:
C) Contact
Explanation:
The magnet requires almost direct <u>contact</u> with the fridge to start its magnetic properties.