Advertisements
Advertisements
Question
Why are concave mirrors used in solar devices?
Advertisements
Solution
A concave mirror is also known as a converging mirror because of its ability to focus parallel rays of light at a single point on its focal plane. This property is used in solar devices. Parallel rays from the Sun, when reflected by the concave mirror, are focused at a particular point, generating a significant amount of heat. This heat is essential for the proper functioning of solar devices, such as solar cookers or solar furnaces.
APPEARS IN
RELATED QUESTIONS
An object of height 5 cm is placed perpendicular to the principal axis of a concave lens of focal length 10 cm. If the distance of the object from the optical centre of the lens is 20 cm, determine the position, nature and size of the image formed using the lens formula.
State two positions in which a concave mirror produces a magnified image of a given object. List two differences between the two images.
A spherical mirror produces an image of magnification −1 on a screen placed at a distance of 40 cm from the mirror:
(i) Write the type of mirror.
(ii) What is the nature of the image formed?
(iii) How far is the object located from the mirror?
(iv) Draw the ray diagram to show the image formation in this case.
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
Which type of mirror is used by a dentist?
For what position of an object, a concave mirror forms a real image equal in size to the object?
With the help of a ray diagram, determine the position, nature and size of the image formed of an object placed at the centre of curvature of a concave mirror.
In the concave reflector of a torch, the bulb is placed:
(a) between the pole and focus of reflector
(b) at the focus of reflector
(c) between focus and centre of curvature of reflector
(d) at the centre of curvature of reflector
An object is 100 mm in front of a concave mirror which produces an upright (erect image). The radius of curvature of the mirror is ______.
A concave mirror has a focal length of 25 cm. At which of the following distance should a person hold his face from this concave mirror so that it may act as a shaving mirror?
(a) 45 cm
(b) 20 cm
(c) 25 cm
(d) 30 cm
Give reason for your choice.
Between which two points of concave mirror should an object be placed to obtain a magnification of:
(a) −3
(b) +25
(c) −0.4
What type of mirror should be used as a shaving mirror?
What would your image look like if you stood close to a large:
concave mirror?
Complete the following diagrams in figure by drawing the reflected rays for the incident rays 1 and 2 if F is the focus and C is the centre of curvature.
State two uses of a concave mirror.
A student obtained a sharp image of the grills of a window on a screen using a concave mirror. His teacher remarked that for getting better results a well lit distant object (preferably the sun) should be focussed on the screen. What should be done for this purpose?
(A) Move the screen slightly away from the mirror
(B) Move the mirror slightly towards the screen
(C) Move the screen and the mirror away from the object
(D) Move the screen and the mirror towards the object
Match the following.
| Convex mirror | Radio telescopes |
| Parobolic mirror | Rear – view mirror |
| Snell’s law | Kaleidoscope |
| Dispersion of light | sin i/sin r =μ |
| Refractive index | Rainbow |
Which of the following can make a parallel beam of light when light from a point source is incident on it?
______ mirrors make things look larger when objects are placed close to them.
To obtain an image twice the size of the object, between which two points related to a concave mirror should an object be placed?
