Question

A clock is moving across your line of sight with its face turned toward you. Which of the following statements about this clock, as seen by you, is NOT correct?

A) The clock will run slow compared with a clock in your hand.
B) The clock will appear shorter than it would if it were at rest.
C) The clock will appear thinner, front to back, than it would if it were at rest.
D) The clock will appear denser than it would if it were at rest.

Answer 1

The incorrect statement about the clock moving across your line of sight is B) The clock will appear shorter than it would if it were at rest, as the clock would experience length contraction, appearing thinner but not shorter.

Step-by-step explanation:

The question relates to the effects of relativistic motion on the perception of time and space of a clock moving across your line of sight with its face turned towards you. Statement A) is correct; due to time dilation, the moving clock will run slow compared to a stationary clock. Statement B) is incorrect; the clock will not appear shorter but would experience length contraction along the direction of motion, appearing thinner but not shorter. Statement C) is correct; length contraction would make the clock appear thinner front to back. Statement D) is wrong as density is a property dependent on mass and volume, and while length contraction affects spatial dimensions, it does not imply a change in the clock's density.