Questions from College Physics

Q: A point source of light is placed 10 cm in front of

A point source of light is placed 10 cm in front of a concave mirror; the reflected rays are parallel. What is the radius of curvature of the mirror?

Q: A sample of potassium-40 has an activity of 9.

A sample of potassium-40 has an activity of 9.0 mCi. What is its mass?

Q: An object 8.0 cm high forms a virtual image 3

An object 8.0 cm high forms a virtual image 3.5 cm high located 4.0 cm behind a mirror. (a) Find the object distance. (b) Describe the mirror: is it plane, convex, or concave? (c) What are its foca...

Q: A 115 g ball is traveling to the left with a speed

A 115 g ball is traveling to the left with a speed of 30 m/s when it is struck by a racket. The force on the ball, directed to the right and applied over 21 ms of contact time, is shown in the graph....

Q: An alpha particle produced in radioactive decay has a kinetic energy of

An alpha particle produced in radioactive decay has a kinetic energy of typically about 6 MeV. When an alpha particle passes through matter (e.g., biological tissue), it makes ionizing collisions with...

Q: An object is placed 10.0 cm in front of a

An object is placed 10.0 cm in front of a lens. An upright, virtual image is formed 30.0 cm away from the lens. What is the focal length of the lens? Is the lens converging or diverging?

Q: A 65 kg patient undergoes a diagnostic chest x-ray and

A 65 kg patient undergoes a diagnostic chest x-ray and receives a biologically equivalent dose of 0.2 mSv distributed over 33% of the patient’s body mass. If the x-rays have a relative biological effe...

Q: A concave mirror has a radius of curvature of 14 cm.

A concave mirror has a radius of curvature of 14 cm. If a pointlike object is placed 9.0 cm away from the mirror on its principal axis, where is the image?

Q: If meat is irradiated with 2000.0 Gy of x-

If meat is irradiated with 2000.0 Gy of x-rays, most of the bacteria are killed and the shelf life of the meat is greatly increased. (a) How many 100.0 keV photons must be absorbed by a 0.30 kg steak...

Q: A 5.0 cm tall object is placed 50.0

A 5.0 cm tall object is placed 50.0 cm from a lens with focal length −20.0 cm. (a) How tall is the image? (b) Is the image upright or inverted?