A convex lens has a focal length of 20 cm. If an object is placed at a distance of 30 cm from the lens, what is the distance of the image from the lens?
Practice Questions
1 question
Q1
A convex lens has a focal length of 20 cm. If an object is placed at a distance of 30 cm from the lens, what is the distance of the image from the lens?
60 cm
15 cm
30 cm
10 cm
Using the lens formula 1/f = 1/v - 1/u, we find v = 60 cm.
Questions & Step-by-step Solutions
1 item
Q
Q: A convex lens has a focal length of 20 cm. If an object is placed at a distance of 30 cm from the lens, what is the distance of the image from the lens?
Solution: Using the lens formula 1/f = 1/v - 1/u, we find v = 60 cm.
Steps: 9
Step 1: Identify the given values. The focal length (f) of the lens is 20 cm, and the object distance (u) is -30 cm (we use a negative sign for object distance in lens formula).
Step 2: Write down the lens formula: 1/f = 1/v - 1/u.
Step 3: Substitute the known values into the lens formula: 1/20 = 1/v - 1/(-30).
Step 4: Simplify the equation: 1/20 = 1/v + 1/30.
Step 5: Find a common denominator for the right side of the equation. The common denominator for 20 and 30 is 60.
