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प्रश्न
Find the odd one out and give its explanation.
विकल्प
Eye piece
Magnifier
Kaleidoscope
Telescope
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उत्तर
Kaleidoscope
Explanation-
Kaleidoscope uses mirrors while other devices make use of lenses.
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संबंधित प्रश्न
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
A ray of light travelling in water emerges into air. Draw a ray-diagram indicating the change in its path.
Draw a labelled ray diagram to show how a ray of light passes through a parallel-sided glass block if it hits the glass block at an angle other than 90° (that is, obliquely to the glass block).
What type of lens would you use as a magnifying glass? How close must the object be to the lens?
Fill in the following blank with suitable word:
The image in a convex lens depends upon the distance of the ........... from the lens.
You eye contains a convex lens. Why is it unwise to look at the sun?
A convex lens has a focal length of 10 cm. At which of the following positions should an object be placed so that this convex lens may act as a magnifying glass?
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
A convex lens of focal length 10 cm is placed in contact with a concave lens of focal length 20 cm. The focal length of this combination of lenses will be:
(a) +10 cm
(b) +20 cm
(c) −10 cm
(d) −20 cm
The diagram alongside shows the refraction of a ray of light from sir to a liquid.
(a) write the values of (i) angle of incidence, (ii) angle of refraction.
(b) use snell’s law to find the refractive index of liquid with respect to air.
The focal length of a thin convex lens is ______ than that of a thick convex lens.
Write the three characteristics of the image formed by a convex lens of focal length 20 cm for the object at distance (i) 10 cm, (ii) 30 cm, (iii) 40 cm, (iv) 60 cm from the lens.
Can a normal convex lens behave like a concave lens and vice-versa?
Why do we say that the ‘2F’ and ‘F’ points of a convex lens can be regarded as a sort of ‘turning points’ as far as the nature of the image formed by it is concerned?
An object is placed in front of a convex lens such that the image formed has the same size as that of the object. Draw a ray diagram to illustrate this.
Diagram shows an object AB placed on the principal axis B of a convex lens placed in air. F1 and F2 are the two foci of the lens.
(i) Copy the diagram:
Draw a ray of light starting from B and passing through O. Show the same ray after refraction by the lens. Draw another ray from B which passes through F2 after refraction by the lens. Locate the final image
(ii) Is the image real or virtual?
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
: Object near the lens : : ______ : 
Which of the following statements is true?
