Question

Which of the following must always be the same: a. Time - a second for example b. Distance - a meter for example The speed of Light - 3E8 m/s d. Weight - how much does an apple weight.

Answer 1

Answer:

The speed of light remains the same.

Explanation:

(a)  Time : second, hour minutes are example of time.

(b) Distance : meter, kilometers etc are some example of distance.

(c) The speed of light : It always remains constant. It is equal to $3\times 10^8\ m/s$.

(d) The weight of an object is given by the product of mass of an object and the acceleration due to gravity. As the value of g is not same everywhere, its weight varies.

So, the speed of light is always remains the same. Hence, the correct option is (c).