Question

Which of the following lenses would you prefer to use while reading small letters found in a dictionary?
(A). A convex lens of focal length 50cm
(B). A concave lens of focal length 50cm
(C). A convex lens of focal length 5cm
(D). A concave lens of focal length 5cm

Answer 1

- Hint: A convex lens is a converging lens. At the point when parallel rays of light go through a convex lens, the refracted rays always converge at one point which is called the principal centre. The separation between the principal centre and the focal point of the lens is known as the focal length.

Complete step-by-step solution:
A convex lens is likewise utilized as a simple microscope. The object is kept between the focal length and mirror so a virtual, erect and magnified image is framed. Littler focal length has more power and is reasonable for larger magnification.
The point at which the light enters the lens relies upon the distance of the object from the lens. In the event that the object is near the lens the light rays enter at a sharper angle. These outcomes in the rays converge endlessly from the lens. As the lens can just curve the light to a certain concur the image should be focussed so as to frame on the film. This is accomplished by moving the lens away from the film.
Consequently, the real image of a closer object shapes further away from the lens than the genuine image of a removed object and the activity of centring is the moving of the taken lens to get the real image to reflect on the film.
The image frame is supposed to be real on the grounds that the rays of light from the object go through the film and transform (upside down).
Subsequently, a convex lens of focal length 5 cm is preferred. Hence, option C is correct.

Note: Essentially, if the object is away from the lens the rays enter at a more extensive point. This results in the rays being refracted at a more honed point and the image shaping nearer to the lens. For this situation the lens should be situated nearer to the film to get an engaged image.