Normal type of MCQ with one correct option
Two objects A and B when placed in turn in front of a concave mirror of focal length 7.5 cm, give images of equal size. If A is three times the size of B and is placed 30 cm from the mirror, what is the distance of B from the mirror?
10 cm
12.5 cm
15 cm
17.5 cm
Normal type of MCQ with one correct option
The sun’s disc subtends an angle of 10-2 rad at the earth. What must be radius of curvature of the mirror which will produce on a screen an image of the sun 2 cm in diameter?
1 m
2 m
3 m
4 m
Normal type of MCQ with one correct option
A motor car is fitted with a convex driving mirror of focal length 20 cm. A second motor car 2.1 m broad and 1.05 m high is 4 m behind the first car. What is the size of the image of the second car as seen in the mirror of the first?
Breadth = 8 cm, height = 4 cm
Breadth = 10 cm, height = 5 cm
Breadth = 12 cm, height = 6 cm
Breadth = 14 cm, height = 7 cm
A,B
B
C,D
A,B & D
Comprehension
When two coherent sources interact with each other there will be production of alternate bright and dark fringes on the screen The young’s double slit experiment demonstrate the idea of making two coherent sources. For better visibility, one has to choose proper amplitude for the sources. The phenomena are good enough to satisfy the conversion of energy principle. The pattern formed in YDSE is of uniform thickness and is nicely placed on a long distance screen. Law of conservation of energy is satisfied because:
Equal loss and gain in intensity is observed
All bright fringes are equally bright
All dark fringes are of zero brightness
Equal loss and gain in intensity on screen is equal to sum of intensities of the two sources.
Y1 , Y2 only
Y2, Y3 only
Y3, Y4 only
none of these
Both A and R are true and R is correct explanation of A
Both A and R are true and R is not correct explanation of A
A is true, R is false
A is false, R is true
f,2
f
3f,2
2f
Amplitudes of sources are equal
The width of the slits should not be equal
Dark should be the darkest and bright should be the brightest.
The widths should be the same