Myopia can be corrected by using
concave lenses
contact lenses
prismatic lenses
convex lenses
A concave mirror cannot be used as :
a magnifying mirror
a torch reflector
a dentist's mirror
a rear view mirror
A young man has to hold a book at arm's length to be able to read it clearly.The defect of vision is :
astigmatism
myopia
presbyopia
hypermetropia
With both eyes open, a person's field of view is about :
90°
150°
180°
360°
The defect of vision which cannot be corrected by using spectacles is :
cataract
Linear magnification (m) produced by a rear view mirror fitted in vehicles :
is equal to one
is less than one
is more than one
can be more or less than one depending on the position of object
The focal length of a spherical mirror of radius of curvature 30 cm is :
10 cm
15 cm
20 cm
30 cm
Which type mirror is used in box-type solar cooker?
Spherical mirror
Convex mirror
Plane mirror
Concave mirror
A virtual image is one which
can be taken on a screen
cannot be taken on a screen
sometimes can be and sometimes cannot be taken on a screen
is formed only by a concave mirror
If R is the radius of curvature of a spherical mirror and f is its focal length,then :
R = f
R = 2f
R = f/2
R = 3f