2nd Year Physics Chapter 9 Test23. Cosmology

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. The balloon model shows that as the balloon expands:
   1. Dots remain at the same distance
   2. Dots move closer
   3. Dots move farther apart
   4. Dots disappear
2. Another important example of a standard candle is:
   1. Type 1A supernovae
   2. Pulsars
   3. White dwarfs
   4. Black dwarfs
3. Which law states that brightness of a source is inversely proportional to the square of its distance
   1. Law of brightness
   2. Direct Square Law of brightness
   3. Inverse Square Law of brightness
   4. Inverse Square Law of light
4. Luminosity depends on
   1. Size of the star
   2. Temperature of the star
   3. Colour of the star
   4. Option 1 and 2
5. A black body is:
   1. A perfectly reflecting object
   2. A perfectly transparent object
   3. An ideal, perfectly opaque and non-reflecting object
   4. A partial absorber
6. The absorption and emission spectra of an element are:
   1. Identical
   2. Inverse of each other
   3. Random
   4. Independent
7. The orbit height of the Hubble Space Telescope above Earth is:
   1. 200 km
   2. 340 km
   3. 540 km
   4. 1500 km
8. The James Webb Space Telescope was launched in:
   1. 2015
   2. 2018
   3. 2021
   4. 2024
9. The Doppler effect is a change in:
   1. Mass
   2. Velocity
   3. Wavelength or frequency
   4. Brightness
10. SI unit of Luminosity is
    1. watts
    2. joules
    3. newtons/meter
    4. cd/m