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प्रश्न
_______ times larger images can be obtained by using a simple microscope.
विकल्प
5
10
20
60
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उत्तर
20 times larger images can be obtained by using a simple microscope.
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संबंधित प्रश्न
An object is placed at a distance of 15 cm from a concave lens of focal length 30 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.
If the image formed by a convex lens is of the same size as that of the object, what is the position of the image with respect to the lens?
For what position of an object a real, diminished image is formed by a convex lens?
An object is placed f and 2f of a convex lens. Which of the following statements correctly describes its image?
(a) real, larger than the object
(b) erect, smaller than the object
(c) inverted, same size as object
(d) virtual, larger than the object
A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:
A burning candle whose flame is 1.5 cm tall is placed at a certain distance in front of a convex lens. An image of candle flame is received on a white screen kept behind the lens. The image of flame also measures 1.5 cm. If f is the focal length of convex lens, the candle is placed:
(a) at f
(b) between f and 2f
(c) at 2f
(d) beyond 2f
An object 2 cm tall is placed on the axis of a convex lens of focal length 5 cm at a distance of 10 m from the optical centre of the lens. Find the nature, position and size of the image formed. Which case of image formation by convex lenses is illustrated by this example?
Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:
0.15 m
What type of images can a convex lens make?
An image formed on a screen is three times the size of the object. The object and screen are 80 cm apart when the image is sharply focussed.
- State which type of lens is used.
- Calculate focal length of the lens.
What kind of lens is used to correct
long-sightedness?
A lens forms an erect, magnified, and virtual image of an object.
- Name the type of lens.
- Draw a ray diagram to show the formation of the image.
- Where is the object placed in relation to the lens?
- Name the device which uses this principle.
A student focussed the image of a distant object using a device ‘X’ on a white screen ‘S’ as shown in the figure. If the distance of the screen from the device is 40 cm, select the correct statement about the device.
(A) The device X is a convex lens of focal length 20 cm.
(B) The device X is a concave mirror of focal length 40 cm.
(C) The device X is a convex mirror of radius of curvature 40 cm.
(D) The device X is a convex lens of focal length 40 cm.
For which position of the object does a convex lens form a virtual and erect image? Explain with the help of a ray diagram.
Draw neat diagram to show the
Convergent action of a convex lens,
Out of the two lenses one concave and the other convex state which is a convergent or a divergent type of a lens. Give a reason for your answer.
What happens to the image formed by a convex lens if its lower part is blackened?
Which lens can produce a real and inverted image of an object?
_______ is a combination of two convex lenses with small focal length.
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
