Question

Thrree students A, B and C focussed a distant building on a screen with the help of a
concave mirror. To determine focal length of the concave mirror they measured the
distances as given below :
Student A : From mirror to the screen
Student B : From building to the screen
Student C : From building to the mirror
Who measured the focal length correctly :
a) Only A b)Only B c)A and C d)B and C

Answer 1

Answer:

(i) 21-17=(4), 5+7=12÷2=(6)

6×4=24

(ii)28-25=(3), 13+7=20÷2=(10)

10×3=30

(iii)16-10=(6),8+2=10÷2=(5)

6×5=30

Right Answar is 30