(a) A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are
placed in close contact with one another:
(i) What is the power of this combination?
(ii) What is the focal length of this combination?
(iii) Is this combination converging or diverging?
Answers
Answered by
3
Answer:
Answer
f
1
=25cm=0.25m
P
1
=
f
1
1
=
0.25
1
=4D
f
2
=−10cm=−0.1m
P
2
=
f
2
1
=
−0.1
1
=−10D
(a) Power of the combination :
P=P
1
+P
2
=4D+(−10D)
=−6D
(b) Focal length of the combination:
f=
P
1
=
−6
1
=−0.1666m=−16.66cm
(c) The combination has negative focal length , so it is diverging.
Answered by
3
Step-by-step explanation:
f
1
=25cm=0.25m
P
1
=
f
1
1
=
0.25
1
=4D
f
2
=−10cm=−0.1m
P
2
=
f
2
1
=
−0.1
1
=−10D
(a) Power of the combination :
P=P
1
+P
2
=4D+(−10D)
=−6D
(b) Focal length of the combination:
f=
P
1
=
−6
1
=−0.1666m=−16.66cm
(c) The combination has negative focal length , so it is diverging.
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