# Worksheet: Telescopes

Q1:

What is the angular magnification of a telescope that has a 100 cm-focal length objective and a 2.50 cm-focal length eyepiece?

• A x
• B x
• C x
• D x
• E x

Q2:

A 7.5x binocular produces an angular magnification of , acting like a telescope. (Mirrors are used to make the image upright.) If the binoculars have objective lenses with a 75.0-cm focal length, what is the focal length of the eyepiece lenses?

Q3:

Two stars that are km apart are viewed by a telescope and found to be separated by an angle of radians . If the eyepiece of the telescope has a focal length of 1.5 cm and the objective has a focal length of 3 meters, how far away are the stars from the observer?

• A km
• B km
• C km
• D km
• E km

Q4:

A planet at a distance of m from Earth is observed by a telescope that has a focal length of the eyepiece of 1 cm and a focal length of the objective of 1 cm. The planet is seen to subtend an angle of rad at the eyepiece. What is the size of the planet?

• A m
• B m
• C m
• D m
• E m

Q5:

A large reflecting telescope has an objective mirror with a 10.0-m radius of curvature. What angular magnification does it produce when a 3.00 m-focal length eyepiece is used?

• A x
• B x
• C x
• D x
• E x

Q6:

A telescope can be used to enlarge the diameter of a laser beam and limit diffraction spreading. The laser beam is sent through the telescope in the direction opposite to the normal one and can then be projected onto a satellite or the Moon. This is done with a telescope, producing a 3.50 m diameter beam of 630 nm wavelength light.

What is the minimum angular spread of the beam produced?