Question

a student wants draw diagram for formation of a real image at 2f of a convex lens . for he must take the object placed at a.infinity b.focus c.between optical center and focus d.2f​

Answer 1

The object should be taken at (d) 2f.

Answer 2

answer : option (d) 2f

a student wants to draw diagram for formation of a real image at 2f of a convex lens.

image distance, v = 2f

focal length of convex lens = f

using lens maker formula, 1/v - 1/u = 1/f

⇒1/2f - 1/u = 1/f

⇒1/2f - 1/f = 1/u

⇒1/u = 1/-2f

⇒u = -2f

hence object is placed at 2f left side of convex lens. option (d) is correct choice .

also read questions :a particle is projected with speed u at angle theta with horizontal from ground. if it is at same height from ground at ...

https://brainly.in/question/4913928

A particle is projected upwards. The times corresponding to height h while ascending and descending are t1 and t2 respec...

https://brainly.in/question/1181454