12th Grade Physics Exam: Quiz!
(183).jpg "12th Grade Physics Exam: Quiz!")
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- 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.
Radiation
- 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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