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प्रश्न
Which type of mirror is used in the following?
Street lights
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उत्तर
Convex mirror
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संबंधित प्रश्न
Analyse the following observation table showing variation of image distance (v) with object distance (u) in case of a convex lens and answer the questions that follow, without doing any calculations:
| S. No. | Object distance u(cm) | Image distance v(cm) |
| 1 | −90 | +18 |
| 2 | −60 | +20 |
| 3 | −30 | +30 |
| 4 | −20 | +60 |
| 5 | −18 | +90 |
| 6 | −10 | +100 |
(a) What is the focal length of the convex lens? Give reason in support of your answer.
(b) Write the serial number of that observation which is not correct. How did you arrive at this conclusion?
(c) Take an appropriate scale to draw ray diagram for the observation at S. No. 4 and find the approximate value of magnification.
If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a labelled ray diagram to support your answer.
Which type of mirror has:
- positive focal length?
- negative focal length?
Which mirror has a wider field of view?
A ray of light of going towards the focus of a convex mirror becomes parallel to the principal axis after reflection from the mirror. Draw a labelled diagram to represent this situation.
Where would the image be formed by a convex mirror if the object is placed:
between infinity and pole of the mirror?
Draw labelled ray-diagrams to show the formation of image in both the case.
Give two uses of a convex mirror. Explain why you would choose convex mirror for these uses.
What happens to the image when the object is moved away from the mirror gradually?
An object is kept at a distance of 5 cm in front of a convex mirror of focal length 10 cm. Calculate the position and magnification of the image and state its nature.
An object 1 cm tall is placed 30 cm in front of a convex mirror of focal length 20 cm. Find the size and position of the image formed by the convex mirror.
A ray of light passing through centre of curvature of a spherical mirror, after reflection
The image formed by a convex mirror is
A driver uses a convex mirror as a rearview mirror. Explain the reason with the help of a ray diagram.
To determine the focal length of a convex lens by obtaining a sharp image of a distant object we generally follow the following steps which are not in proper sequence.
(a) Hold the lens between the object and the screen
(B) Measure the distance between the lens and the screen
(C) Select a well lit distant object
(D) Place a screen opposite to the object on the lab table
(e) Adjust the position of the lens to form a sharp image
The correct sequence of these steps is:
(A) c, a, d, e, b
(B) c, d, a, e, b
(C) c, d, e, a, b
(D) c, a, e, d, b
State whether true or false. If false, correct the statement.
The convex mirror always produces a virtual, diminished and erect image of the object.
Numerical problem.
A concave mirror produces three times magnified real image of an object placed at 7 cm in front of it. Where is the image located? (Ans: 21 cm in front of the mirror)
The image formed by these mirrors is ______ than the object.
Assertion: Convex mirrors are used as a rearview mirror in vehicles for observing traffic at our back.
Reason: A convex mirror has a much larger field of view.
Match the following.
| Column I | Column II |
| Convex mirror | Radio telescopes |
| Parabolic mirror | Rear-view mirror |
| Snell’s law | Kaleidoscope |
| Dispersion of light | sin i/sin r =μ |
| Refractive index | Rainbow |
