# 12th Grade Physics Exam: Quiz!

14 Questions | Total Attempts: 139  Settings  . Preparing for the 12th-grade physics exam? Ready to take the quiz? As it pertains to this quiz, you must understand how many electron volts make up 1 joule and the electrons ejected from metals because of the effect of light. What is the refractive directory of the core in optical fibers, the angle of minimum deviation, and a wavefront due to a source situated at infinity? Good luck with this quiz.

• 1.
An electron, an alpha-particle, and a proton have the same kinetic energy. Which of these particles has the shortest de Broglie wavelength?
• A.

A. electron

• B.

B. proton

• C.

C. alpha-particle

• 2.
How many electron volts makeup 1 Joule?
• A.

(a) 6.25×10^18 eV.

• B.

(b) 1.25×10^181 eV

• C.

(c) 6.25×10^16 eV.

• 3.
If the maximum Kinetic energy of electrons emitted in a photo-cell is 6 eV. What is the stopping potential?
• A.

3 V

• B.

12 V

• C.

6 V

• 4.
The electrons ejected from metals due to effect of light are called
• A.

Primary electrons

• B.

Thermions

• C.

Photoelectrons

• 5.
The frequency of the incident light falling on a photosensitive metal plate is doubled, stopping potential will be:
• A.

Double the earlier value

• B.

Unchanged

• C.

More than doubled

• 6.
A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen.
• A.

(a) half the image will disappear.

• B.

(b) intensity of image will decrease but complete image is formed.

• C.

(c) intensity of image will increase but image is not distinct.

• 7.
In optical fibers, the refractive index of the core is:
• A.

Greater than that of the cladding.

• B.

Smaller than that of the cladding.

• C.

Equal to that of the cladding.

• 8.
A metal coin is at bottom of a beaker filled with a liquid of refractive index = 4/3 to a height of 6 cm. To an observer looking from above the surface of the liquid, coin will appear at a depth.
• A.

(a) 1.5 cm

• B.

(b) 4.5 cm

• C.

(c) 6.75 cm

• D.

Option 4

• 9.
The refractive index of the material of an equilateral prism is √3. What is the angle of minimum deviation?
• A.

(a) 45°

• B.

(b) 60°

• C.

(c) 37°

• D.

Option 4

• 10.
In an experiment to find the focal length of a concave mirror, a graph is drawn between the magnitude of u and v. The graph looks like?
• A.

Option 1

• B.

Option 2

• C.

Option 3

• 11.
The wavefront due to a source situated at infinity is:
• A.

Spherical

• B.

Planar

• C.

Cylindrical

• 12.
A laser beam is coherent because it contains:
• A.

(a) waves of several wavelengths.

• B.

(b) coherent waves of a single wavelength.

• C.

(c) coherent waves of several wavelengths

• 13.
According to Huygens’ principle, light is a form of
• A.

Particle

• B.

Wave

• C.

• 14.
Two coherent monochromatic light beams of intensities I and 41 superimpose. The maximum and minimum possible intensities in the resulting beam are:
• A.

(a) 5I and I

• B.

(b) 5I and 3I

• C.

(d) 9I and I

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