Pre assessment 29th aug

Speed of light =

• a. 3X10⁸ m/s

• b. 3X10⁶ m/s

• c. 3X10^-8 m/s

• d. 3X10^-6 m/s

The phenomenon of change in direction of a wave passing from one medium to another is called

• a. Reflection
• b. Dispersion
• c. Refraction
• d. Radiation

Wavelength of visible light is

• a. 400 mm to 780 mm
• b. 400 nm to 780 nm
• c. 4000 m to 7800 m
• d. 40 nm to 78 nm

Which of the following lights have shortest wavelength

• a. Violet
• b. Blue
• c. Orange
• d. Red

Which colored light scatters least by fog and smoke?

• a. Green
• b. Yellow
• c. Red
• d. Blue

The concave lens have _______ focal length

• a. Positive
• b. Negative
• c. Zero
• d. Both b and c

The colors in the rainbow are formed due to

• a. Reflection
• b. Diffusion
• c. Refraction
• d. Dispersion

The Concave lens is used as a remedy in which of the following defects in the eye?

• a. Hyper-metropia
• b. Myopia
• c. Astigmatism
• d. Presbyopia

What will be the power of the concave lens of focal length 5 m?

• a. 5 D
• b. - 5 D
• c. - 0.2 D
• d. 0.2 D

Mirage is a phenomenon due to

• a. refraction of light
• b. reflection of light
• c. diffraction of light
• d. Total internal reflection