Solutions - CBSE Class 10 Sample Paper for 2022 Boards - Science [MCQ]

Question 43 - Solutions - CBSE Class 10 Sample Paper for 2022 Boards - Science [MCQ] - Solutions to CBSE Sample Paper - Science Class 10

Last updated at Oct. 11, 2021 by Teachoo

If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens?

Question 43 If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens? (A) -80cm (B) -40 cm (C) -40/3 cm (D) -80/3 cm As image is real, it will also be inverted
∴ Magnification is negative
Thus,
m = −3
Also,
Distance between lens and image is 80 cm
Since it is a real image, image Distance will be positive.
∴ V = 80 cm
We need to find,
At what distance should candle be from the lens
∴ we need to find u
Now,
m = 𝑉/𝑢
−3 = 80/4
u = 80/(−3)
u = − 𝟖𝟎/𝟑 cm
So, the correct answer is (D)

Made by

CA Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 12 years and a teacher from the past 16 years. He teaches Science, Accounts and English at Teachoo