Advertisements
Advertisements
प्रश्न
According to cartesion sign convention, which mirror and which lens has negative focal length?
उत्तर
Concave mirror is having a negative focal length.
APPEARS IN
संबंधित प्रश्न
To construct ray diagrams, two rays of light are generally so chosen that it is easy to determine their directions after reflection from a mirror. Choose two such rays and state the path/direction of these rays after reflection from a concave mirror. Use these two rays to find the position and nature of the image of an object placed at a distance of 8 cm from a concave mirror of focal length 12 cm.
Name the type of mirror used in the following situation:
Headlights of a car
Support your answer with reason.
Fill in the following blank with suitable word:
The focal length of a concave mirror is the distance from the ......... to the mirror.
For what position of an object, a real and diminished image is formed by a concave mirror?
The diagram shows a dish antenna which is used to receive television signals from a satellite. The antenna (signal detector) is fixed in front of the curved dish.
Figure
(a) What is the purpose of the dish?
(b) Should it be concave or convex?
(c) Where should the antenna be positioned to receive the strongest possible signals?
(d) Explain what change you would expect in the signals if a larger dish was used.
A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting best result he should focus
(A) a distant tree or an electric pole
(B) a well-illuminated distant building
(C) well-lit grills of the nearest window
(D) a burning candle laced at the distant edge of the laboratory table
Answer the following question:
An object is placed at a distance of 30 cm from a concave lens of focal length 30 cm.
(i) Use the lens formula to determine the distance of the image from the lens.
(ii) List four characteristics of the image (nature, position, size, erect/inverted) in this case.
(iii) Draw a labelled diagram to justify your answer of the part (ii)
The image formed by concave mirror is real, inverted and of the same size as that of the object. The position of object should be ______.
In torches, searchlights, and headlights of vehicles, the bulb is placed ______ of the concave mirror.
Which type of mirror is used in the following?
Shaving mirror
