A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting the best result he should focus
A. a distant tree or an electric pole
B. a well-illuminated distant building
C. well-lit grills of the nearest window
D. a burning candle placed at the distant edge of the laboratory table
Answer:A
A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting the best result he should focus
A. a distant tree or an electric pole B. a well-illuminated distant building C. well-lit grills of the nearest window D. a burning candle placed at the distant edge of the laboratory table
Explanation: The object should be not very far and well lit.