An object is placed at a distance of 5f/4 from a concave mirror of focal length f. The mirror produces a real image ______ times the size of the object
Physics · Mixed Chapter
JEE Mains

Question

An object is placed at a distance of 5f/4 from a concave mirror of focal length f. The mirror produces a real image ______ times the size of the object

G1 Physics · Accepted Answer

Step 1: Let the concave mirror have focal-length magnitude f. Object distance is u=5f/4. Step 2: Real-image distance follows 1/f=1/u+1/v, so v=fu/(u−f)=[f(5f/4)]/(f/4)=5f. Step 3: Magnification magnitude =|v/u|=5f/(5f/4)=4. Answer: 4.