Physics Answers

Someday a person will walk on Mars, which is 5.6 x 10¹⁰ m from the earth at the closest approach. Determine the minimum time that will be required for a message from Mars to reach the earth via radio waves.

Question 17 (4 points)

Some car mirrors are curved such that the image is smaller than it would be if plane mirrors were used in order to give a wider field of view. If a car is located 25.0 cm away and looks 0.2 times the size it would normally be, find the local length of this mirror.

Question 17 options:

A)

No option is correct

B)

-6.25 cm

C)

-4.25 cm

D)

-5.25 cm

E)

-3.25 cm

Question 15 (2 points)

Which of the following best describes the image formed by a concave mirror when the object distance from the mirror is less than the focal length (f)?

Question 15 options:

A) 

No option is correct

B) 

Real, inverted and reduced

C) 

Virtual, upright and enlarged

D) 

Real, inverted and enlarged

E) 

Virtual, upright and reduced

Question 13 (4 points)

A concave mirror has a radius of curvature of 40.5 cm and is positioned at a distance such that the upright image of a person's face is 1.5 times the size of his face. How far is the mirror from the person's face?

Question 13 options:

A) 

No option is correct

B) 

+4.75 cm

C) 

+ 5.75 cm

D) 

+3.75 cm

E) 

+ 6.75 cm

A bug flying at eye level is located 15 cm in front of a plane mirror. If you are 65 cm from the bug and looking into the mirror, find the distance between your eyes and the apparent position of the bug's image in the mirror.

Question 11 options:

A) 

100 cm

B) 

95 cm

C) 

75 cm

D) 

85 cm

E) 

No option is correct

Question 10 (4 points)

On the + y axis a laser is located at y = + 3.0 cm. The coordinates of a small target are x = + 12.0 cm and y = + 6.0 cm. The + x axis represents the edge-on view of a plane mirror. At what point on the + x axis should the laser be aimed in order for the laser light to hit the target after reflection?

Question 10 options:

A) 

+4 cm

B) 

+3 cm

C) 

-3 cm

D) 

- 4 cm

Question 9 

An object is placed in front of spherical mirror, and the magnification of the system is m = -6. What does this number tell you about the image?

Question 9 options:

A) 

The image is a real image

B) 

No option is correct

C) 

The image is larger than the object

D) 

The image is inverted relative to the object

E) 

a, b and c

Imagine that a motorist is travelling so fast that the yellow light (585 nm wavelength) from a traffic signal appears green (555 nm wavelength). Find the velocity of the motorist, assuming the positive direction is defined as moving closer to the light.

Question 8 options:

A) 

1.64 x 10⁷ m/s

B) 

2.64 x 10⁷ m/s

C) 

3.64 x 10⁷ m/s

D) 

No option is correct

E) 

4.64 x 10⁷ m/s

Electromagnetic waves are

Question 7 options:

A) 

Both longitudinal and transverse

B) 

Transverse

C) 

Longitudinal

D) 

No option is correct

The sun is just covered by a disc of 2cm diameter placed about 2m from the eye. If the length of the diameter of the sun's image formed by a pin-hole camera is 0.5cm. Calculate the distance from the pin-hole to the screen