How is the final image of an astronomical telescope formed?
Inverted
Erected
Neither inverted nor erected
Diminished
An object is placed at a distance of 25cm from a convex lens whose focal length is 10cm. What will be the image distance?
50cm
16.66cm
6.66cm
10cm
A light ray in air enters and passes through a block of glass. What can be started with regard to its speed after it emerging from the block?
Speed is less than when in glass
Speed is less than before it entered glass
Speed is same as that in glass
Speed is same as that before it entered glass
A Convex lens forms a real and inverted image of a needle at a distance of 25cm from a lens. If the image is the same size as that of the needle, where should the needle be placed in front of the lens? Calculate the power of the lens.
the needle be placed at a distance of 25cm in front of the lens and the power is +0.08D
the needle be placed at a distance of 12.5cm in front of the lens and the power is +0.08D
the needle be placed at a distance of 25cm in front of the lens and the power is +8D
the needle be placed at a distance of 12.5cm in front of the lens and the power is +8D
An object is placed 12cm away from a convex lens whose focal length is 10cm. What will the nature of the image formed?
Virtual and enlarged
Virtual and reduced in size
Real and reduced in size
Real and enlarged
Which of the following cannot be considered for the determination of the angle of deviation of a prism?
The refracting angle
The angle of incidence of the ray
The refractive index of the prism material
The thickness of the prism
Combining red and green light (with equal intensity) makes ________ light; combining red and blue light (with equal intensity) makes _______ light; and combining blue and green light (with equal intensity) makes _______ light. Choose the three colors in respective order.
brown, purple, aqua
brown, magenta, yellow
yellow, magenta, brown
yellow, magenta, cyan
An object is placed at a distance of 30.0cm from a thin converging lens a long its axis. The lens has a focal length of 10.0cm. What are the values of the image distance and magnification (respectively)?
60.0 cm and 2.00
15.0 cm and 2.00
60.0 cm and 5.00
15.0 cm and -0.500
Which of the following is false with regard to optical radiation?
the wavelengths of visible light lie between 400nm and 780nm
ultraviolet A has a shorter wavelength than ultraviolet C
the human lens is better at absorbing shorter than longer wavelengths
eclipse burn is caused by infrared radiation
Which of the following describes the best, what will happen to a light ray incident on an air- to- glass - boundary?
Total reflection
Total Transmission
Partial reflection, partial transmission
Partial reflection, total transmission
