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Question 28 in passage 5 of chapter 10 physics TBR
To measure the focal length of a converging lens, parallel light rays are passed through the lens. these rays will meet at the focal point, the distance from the lens to this point can be measured. to measure the focal length for a diverging lens:
A the same procedure can be carried out
B a second diverging lens of known focal length must be employed
C a second converging lens of known focal length must be employed
D diverging lenses do not have a focal length, since light rays are diverged away from the lens axis
The correct answer is C, which i chose through process of elimination; however, I dont understand how a VIRTUAL image can be used as the OBJECT for a converging lens. Doesnt the definition of a virtual image (could not be projected onto a screen) imply that it would not be able to "produce light rays" to be used as the object for a converging lens?
To measure the focal length of a converging lens, parallel light rays are passed through the lens. these rays will meet at the focal point, the distance from the lens to this point can be measured. to measure the focal length for a diverging lens:
A the same procedure can be carried out
B a second diverging lens of known focal length must be employed
C a second converging lens of known focal length must be employed
D diverging lenses do not have a focal length, since light rays are diverged away from the lens axis
The correct answer is C, which i chose through process of elimination; however, I dont understand how a VIRTUAL image can be used as the OBJECT for a converging lens. Doesnt the definition of a virtual image (could not be projected onto a screen) imply that it would not be able to "produce light rays" to be used as the object for a converging lens?
