A10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is [NCERT Exemplar Problems]
A. – 30 cm
B. – 20 cm
C. – 40 cm
D. – 60 cm
Answer:B
A10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is [NCERT Exemplar Problems]
A. – 30 cm B. – 20 cm C. – 40 cm D. – 60 cm