A 5.0-cm real object is placed at a distance of 30.0 cm from a concave mirror of focal length 10.0 cm. Find the location of the image.
A. 6 cm
B. 10 cm
C. 15 cm
D. 60 cm
Is it B. 10 cm?
Which of the following objects can set fire to a piece of paper in the presence of sunlight?
A. Double concave lens
B. Convex lens
C. Convex mirror
D. Concave lens
Is it B?
A 5.0-cm real object is placed at a distance of 30.0 cm from a concave mirror of focal length 10.0 cm.
Find the location of the image.
ANSWER: C
Height of the object = 5.0 cm
Distance = 30.0 cm
Focal length = 10.0 cm
This is the equation:
1/Do + 1/v = 1/f
which means:
1/[distance] + 1/[location] = 1/[Focal length]
1/30.0 + 1/v = 1/10.0
1/ ((1/10.0) - (1/30.0)) = v
14.999999 = v = the location
Which of the following objects can set fire to a piece of paper in the presence of sunlight?
ANSWER: B, convex lens
right on the second. On the first, how can the image be at the focus? That is where infinite distance rays converge.
Oh yeah. I re-did it and the answer is C-15cm...?
For the first question, we can use the mirror formula to find the location of the image. The mirror formula is given by:
1/f = 1/d_o + 1/d_i
Where:
- f is the focal length of the mirror
- d_o is the object distance (distance of the object from the mirror)
- d_i is the image distance (distance of the image from the mirror)
Plugging in the given values:
- f = 10.0 cm
- d_o = 30.0 cm
We can solve for d_i:
1/10 = 1/30 + 1/d_i
Simplifying the equation:
1/10 = (1 + 3/d_i)/30
1/10 = (1 + 3/d_i)/30
Cross-multiplying:
3/d_i = 3
d_i = 1 cm
Therefore, the location of the image is 1 cm. Since none of the options provided match this value, the correct answer is none of the given options.
For the second question, the correct answer is D. Concave lens. Concave lenses converge light rays and can focus them to a point where they can generate enough heat to set fire to a piece of paper in the presence of sunlight.