KVPY Stream SB-SX (Class 12 & 1st Year B.Sc.) Physics: Questions 249 - 252 of 268

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Question number: 249

» Oscillations and Waves » Harmonics

MCQ▾

Question

A wire with linear density of 0.005 kg/m is stretched between two rigid supports. Tension on the wire is 450 N. The wire resonates at 320 Hz. The next frequency at which wire resonates is 360 Hz. The length of the wire is –

Choices

Choice (4) Response

a.

3.75 m

b.

2.0 m

c.

3.0 m

d.

3.25 m

Question number: 250

» Properties of Solids & Liquids » Application of Surface Tension

MCQ▾

Question

Two circular glass plates each of radius R = 15 cm are pressed together with a liquid film of thickness d=2.5×106m . Assuming that the liquid completely wets the glass plates, compute the force normal to plates required to pull them apart. S. T. of liquid = 0.070 N/m.

Choices

Choice (4) Response

a.

3.95 N

b.

2.15 N

c.

4.25 N

d.

2.86 N

Question number: 251

» Dual Nature of Matter and Radiation » De-Broglie Relation

Appeared in Year: 2016

MCQ▾

Question

Electrons accelerated from rest by an electrostatic potential are collimated and sent through a Young’s double slit setup. The fringe width is w . If the accelerating potential is doubled then the width is now close to –

Choices

Choice (4) Response

a.

0.7w

b.

2.0w

c.

1.0w

d.

0.5w

Question number: 252

» Dual Nature of Matter and Radiation » Particle Nature of Light

Appeared in Year: 2016

MCQ▾

Question

Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular are of radius R by a perpendicular magnetic field having a magnitude B . The work function of the metal is –

(Where symbols have their usual meanings)

Choices

Choice (4) Response

a.

hcλme+e2B2R22me

b.

hcλ2me(eBR2me)2

c.

hcλ+2me(eBR2me)2

d.

hcλmec2e2B2R22me

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