MCQ Detailed View

According to Albert Einstein's Theory of Special Relativity, time does not pass at the same rate for all observers. When an object moves at a speed close to the speed of light (3 × 10⁸ m/s), it experiences a phenomenon known as time dilation. This effect makes clocks in motion run slower when observed from a stationary reference frame.Time dilation occurs because space and time are interlinked in what physicists call space-time. At very high velocities, the moving clock’s time is stretched relative to an observer at rest. This is expressed by the time dilation formula:

t′=t1−v2c2t' = \frac{t}{\sqrt{1-\frac{v^2}{c^2}}}t′=1−c2v2t

Where:

• 
  

  t′t't′ = time measured by the moving clock

  
  


• 
  

  $t$ = time in the stationary frame

  
  


• 
  

  $v$ = velocity of the moving clock

  
  


• 
  

  $c$ = speed of light

  
  

As the velocity $v$ approaches the speed of light $c$, the denominator 1−v2/c2\sqrt{1 - v^2/c^2}1−v2/c2 becomes very small, making t′t't′ much larger than $t$. This means less time passes for the moving clock compared to the stationary one—it runs slower.

Real-world evidence for time dilation comes from experiments with atomic clocks placed on fast-moving jets and satellites, which showed measurable differences in time compared to identical stationary clocks. Similarly, muons (subatomic particles) created in the atmosphere live longer when traveling near light speed due to time dilation.

The other options are incorrect:

• 
  

  Fast: Time does not speed up; it slows down.

  
  


• 
  

  Equal to velocity of light: Clocks measure time, not speed.

  
  


• 
  

  Zero velocity: Irrelevant, as moving clocks still have velocity.

  
  

Thus, the correct answer is Slow, as clocks moving at near-light speeds experience slower passage of time relative to stationary observers.