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1. The materials through which objects can be seen but not clearly are called ________ materials.
A. Translucent
B. Transparent
C. Opaque
D. Lustre
ANSWER:A
SOLUTION :The materials through which objects can be seen, but not clearly, are known as translucent.
2. The focal length of the lens of a normal human eye is about______.
A. 25 cm
B. 1 m
C. 2.5 mm
D. 2.5 cm
ANSWER:D
SOLUTION:The focal length of a normal human eye lens is about 2 cm or 20 mm when the eye is relaxed. Focal length is the distance between the eye lens and the retina, which acts as a screen on which the real image is formed.
3. The deviation angle is the lowest _____.
A. Purple
B. Yellow
C. Blue
D. Red
ANSWER:D
SOLUTION:Red
4. Which of the following lens is used to minimize Myopia?
A. Convex lens
B. Concave lens
C. Cylindrical lens
D. None of the above
ANSWER:B
SOLUTION:Concave lenses are used to correct myopia, or shortsightedness. Concave lenses are also known as diverging lenses because they diverge incoming light rays to meet on the retina, making them ideal for myopic eyes.
5. A concave lens always forms ____.
A. A real image
B. A virtual image
C. An image type which depends on object characteristics
D. An image type which depends on lens curvature
ANSWER:B
SOLUTION:A concave lens always forms a virtual image, which is smaller, erect, and diminished in size. A concave lens is a diverging lens, which means it causes light to spread out. The image is formed by the intersection of virtually extended refracted rays.
6. Light enters the eye through a thin membrane called _____.
A. Retina
B. Cornea
C. Pupil
D. Iris
ANSWER:B
SOLUTION :Light enters the eye through a thin, transparent, dome-shaped membrane called the cornea. The cornea is the clear front layer of the eye that bends light to help the eye focus.
7. For the myopic eye, the defect is cured by _____.
A. Convex lens
B. Concave lens
C. Cylindrical lens
D. Toric lens
ANSWER:B
SOLUTION:Ultrasound equipment works at frequencies higher than 20,000 Hz. Ultrasound is sound with a frequency that is above the range of human hearing, which is 20 Hz to 20,000 Hz. Most ultrasound probes operate at frequencies in the megahertz (MHz) range.
8. The optical phenomenon that is responsible for the propagation of light signal through an optical fibre is ________.
A. Interference
B. Scattering
C. Total internal reflection
D. Refraction
ANSWER:C
SOLUTION: The frequency of a sound is proportional to its pitch. An adult man’s voice has a lower pitch than the voices of a baby boy, a baby girl, and a woman.
9. The sun is seen little before it rises and for a short while after it sets. This is because of ________.
A. Total internal reflection
B. Atmospheric refraction
C. Apparent shift in the direction of sun
D. Dispersion
ANSWER:B
SOLUTION: The sun can be seen before it rises and for a short time after it sets due to atmospheric refraction.
10. The ability of a medium to reflect light is also expressed by its _______.
A. Field density
B. Light density
C. Surface density
D. Mass density
ANSWER:B
SOLUTION: The ability of a medium to refract light is also expressed in terms of its optical or Light density. Optical density is not the same as mass density.