Question

what is used as an objective in a reflecting telescope? *
1 point
lense
camera
antenna
mirror
which may be responsible for the accelerating expansion of the universe? *
1 point
big bang
dark matter
dark energy
doppler effect

Explanation:

First Question:

In a reflecting telescope, the objective is a mirror (usually a concave mirror) that gathers and focuses light by reflection. Lenses are used in refracting telescopes, cameras are for imaging (not the objective), and antennas are for radio waves (not optical telescopes). So the correct option is the one with "mirror".

Dark energy is hypothesized to be the force causing the accelerating expansion of the universe. The Big Bang is the origin of the universe, dark matter affects gravitational interactions (not acceleration of expansion), and the Doppler effect is about wave frequency shift (not cosmic expansion cause). So the correct option is the one with "dark energy".

Answer:

D. mirror (assuming the options are labeled A to D as per the order: A. lense, B. camera, C. antenna, D. mirror)

Second Question: