KVPY (Kishore Vaigyanik Protsahan Yojana) Stream SB-SX (Class 12 & 1st Year B.Sc.) Physics: Questions 133 - 135 of 268

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Question number: 133

» Ray Optics » Snell's Law

Appeared in Year: 2015

MCQ▾

Question

Electromagnetic waves emanating from a point A (in air) are incident on a rectangular block of material M and emerge from the other side as shown. The angles i and r are angles of incidence and refraction when the wave travels from air to the medium. Such paths for the rays are possible

Electromagnetic waves travel through block of material M

Electromagnetic Waves Travel Through Block of Material M

In figure electromagnetic waves emanating from point A (in air) are incident on a rectangular block of material M and emerge from the other side.

Choices

Choice (4) Response

a.

only with gamma rays with a wavelength smaller than atomic nuclei of the material

b.

If the material has a refractive index less than zero

c.

If the material has a refractive index very nearly equal to zero

d.

only if the wave travels in M with a speed faster than the speed of light in vacuum.

Question number: 134

» Dual Nature of Matter and Radiation » Photoelectric Effect

Appeared in Year: 2014

MCQ▾

Question

When ultraviolet radiation of a certain frequency falls on a potassium target, the photoelectrons released can be stopped completely by a retarding potential of 0.6 V. If the frequency of the radiation is increased by 10%, this stopping potential rises to 0.9 V. The work function of potassium is

Choices

Choice (4) Response

a.

2.0 eV

b.

2.8 eV

c.

3.0 eV

d.

2.4 eV

Question number: 135

» Thermodynamics » Measurement of Temperature

MCQ▾

Question

Two rods, one made of Aluminum and the other copper of the same length and across sectional area are joined together. (The thermal conductivity of copper is Equation and aluminum is Equation ). If the copper end is held at 1300 C and the aluminum end is held at 50 C, what is the junction temperature (assuming no other heat losses)?

Choices

Choice (4) Response

a.

55.60 C

b.

86.60 C

c.

1000 C

d.

88.70 C

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