I need help with number 1, after that, I should be able to figure the rest of th
ID: 1374939 • Letter: I
Question
I need help with number 1, after that, I should be able to figure the rest of them out.
Explanation / Answer
1) r = 35 cm
f = r/2 = 35/2= 17.5 cm
concave mirror so f = +17.5 cm
a) 60 cm
1/f = 1/u + 1/v
1/17.5 = 1/60 + 1/v
v = 24.705 cm
m = -v/u = - 24.705/60 = -0.41176
negative sign indicates image is real and inverted
m = hi/ho = hi/15
hi = 0.41176*15 = 6.176 mm
image is real,inverted and diminished
b) 20 cm
1/f = 1/u + 1/v
1/17.5 = 1/20 + 1/v
v = 140 cm
m = -v/u = - 140/20 = -7
negative sign indicates image is real and inverted
m = hi/ho = hi/15
hi = 7*15 = 105 mm
image is real,inverted and enlarged
c) 7 cm
1/f = 1/u + 1/v
1/17.5 = 1/7 + 1/v
v = -11.667 cm
m = -v/u = (--11.667 / 7) = +1.67
positive sign indicates image is virtual and upright
m = hi/ho = hi/15
hi = 1.67*15 = 25 mm
image is virtual erect and enlarged.
2) r = 35 cm
f = r/2 = 35/2= 17.5 cm
convex mirror so f = -17.5 cm
a) 60 cm
1/f = 1/u + 1/v
1/-17.5 = 1/60 + 1/v
v = -13.54 cm
m = -v/u = -( -13.54/60) = +0.225
positive sign indicates image is virtual and upright
m = hi/ho = hi/15
hi = 0.225*15 = 3.387 mm
image is virtual,erect and diminished
b) 20 cm
1/f = 1/u + 1/v
1/-17.5 = 1/20 + 1/v
v = 9.33 cm
m = -v/u = - (-9.333/20) = 0.467
positive sign indicates image is virtual and upright
m = hi/ho = hi/15
hi = 0.467*15 = 7 mm
image is virtual erect and diminshed
c) 7 cm
1/f = 1/u + 1/v
1/-17.5 = 1/7 + 1/v
v = -5 cm
m = -v/u = -(-5 / 7) = +0.714
positive sign indicates image is virtual and upright
m = hi/ho = hi/15
hi = 0.714*15 = 10.71 mm
image is virtual erect and diminished.
the same goes with convex and concave lens
convex lens focal length is positive and concave lens focal length is negative
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