An object of height 4 cm is placed at a distance of 24 cms in fornt of a convex lens of focal length 8 cm. Draw ray diagram to find the position of the image. State the characteristics of the image.

Asked by sreenivasanmaralapadu | 15th Jan, 2016, 06:40: PM

Expert Answer:

begin mathsize 12px style Given colon Object space distance comma space straight u equals negative 24 space cm Image space distance comma space straight v equals ? Focal space length comma space straight f equals 8 space cm Using space the space lens space formula 1 over straight f equals 1 over straight v minus 1 over straight u 1 over 8 equals 1 over straight v minus fraction numerator 1 over denominator left parenthesis negative 24 right parenthesis end fraction equals 1 over straight v plus 1 over 24 1 over straight v equals 1 over 8 minus 1 over 24 rightwards double arrow straight v equals 12 space cm end style

Using lens formula, the positive sign shows that the image is to the right of the lens and is at 12 cm from the lens, i.e. the image is formed between F and 2F. Since only the real and inverted image is formed on the right hand=and side of a convex lens, therefore, the image is real and inverted.

begin mathsize 12px style Magnification comma space straight m equals negative straight v over straight u equals 12 over 24 equals negative 0.5 and space straight m equals straight h subscript 2 over straight h subscript 1 space left parenthesis where space straight h subscript 1 space is space size space of space object space and space straight h subscript 2 space is space size space of space image right parenthesis minus 0.5 equals straight h subscript 2 over 4 space space left parenthesis straight h subscript 1 space is space always space positive right parenthesis straight h subscript 2 equals negative 2 space cm Size space of space image space is space 2 space cm. space hence space image space is space space smaller space than space the space object space and space inverted. end style
 

Answered by Priyanka Kumbhar | 18th Jan, 2016, 02:59: PM

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