Given below are few steps (not in proper sequence) followed in the determination of focal length of a given convex lens by obtaining a sharp image of a distant object:
(i) Measure the distance between the lens and screen.
(ii) Adjust the position of the lens to form a sharp image.
(iii) Select a suitable distant object.
(iv) Hold the lens between the object and the screen with its faces parallel to the screen.
The correct sequence of steps for determination of focal length is ____.
(iii), (i), (iv), (ii)
(iii), (iv), (ii), (i)
(iii), (i), (ii), (iv)
(i), (ii), (iii), (iv)
A ray passing through the focus and falling on a convex lens will ____.
retrace its path.
will emerge parallel to principle axis.
will emerge through focus on their side.
None of the above.
The point at the centre of a lens is called as ____.
A convex lens always ____.
neither converges nor diverges
converges or diverges based on object distance
A concave lens always produces ____.
All of the above
The lens which cannot form a real image ____.
A student obtained a sharp image of the grill of a window in the laboratory on a Screen, using a convex lens. For getting better results, her teacher suggested focusing of a distant tree instead of the grill. In which direction should the lens be moved for this purpose to get a sharp image on the screen?
Toward the screen.
Away from the screen.
Behind the screen.
Very far away from the screen.
When red, blue and green light coming parallel to principle axis fall on a convex lens, they will converge on the axis at ____.
Always at one point.
On converging a portion of lens with a black sheet ____.
full image is formed.
full image of reduced brightness is formed.
full image of increased brightness is formed.
size depending on the coverage area.
A convex lens forms an image which is ____.
at focus always
real or virtual depending on the position of object.
A sharp image of a distant object is obtained on a screen by using a convex lens. In order to determine the focal length f the lens, you need to measure the distance between the ____.
lens and the object.
lens and the screen.
object and the screen.
lens and the screen and also object and the screen.
Any ray passing through the optical centre wills ____.
retrace its path.
get converged at focus.
pass through 2f.
Number of trails taken t fined focal length cans ____.
both A and B
bring no change in result
Your school laboratory has one large window. To find the focal length of a concave mirror using one of the walls as the screen, the experiment may be performed ____.
near the wall opposite to the window.
on the same wall as the window.
on the wall adjacent to the window.
only on the table as per the laboratory arrangement.
Focal length of the concave mirror depends on its ____.
radius of curvature
A student obtains a blurred image of an object on a screen by using a concave mirror. In order to obtain a sharp image on the screen, he will have to shift the mirror ____.
towards the screen.
away from the screen.
either towards or away from the screen depending upon the position of the object.
to a position very far away from the screen.
While doing experiments with candle to find focal length of a concave mirror, the candle is placed between ____.
pole and focus
focus and centre of curvature
Image formed by a concave mirror ____.
can be real or virtual.
can be erect or inverted.
can be magnified or diminished.
All of the above.
The nature of image is not affected by the position of the object in ____.
Both A and C