A proton is moving in a uniform magnetic field B in a circular path of radius a in a direction perpendicular to Z-axis along which field B exists. Calculate the angular momentum. If the radius […]
If a magnet is suspended at an angle 30⁰ to the magnetic meridian, the dip needle makes angle of 45⁰ with the horizontal. The real dip is
Options
(a) tan⁻¹(√3/2) (b) tan⁻¹(√3) (c) tan⁻¹(3/√2) […]
In intrinsic semiconductor at room temperature number of electrons and holes are
Options
(a) equal (b) zero (c) unequal (d) infinite
Correct Answer:
equal
Explanation:
No explanation available. Be the first to write […]
what should be the velocity of an electron so that its momentum becomes equal to that of a photon of wavelength 5200 Å?
Options
(a) 700ms⁻¹ (b) 1000ms⁻¹ (c) 1400ms⁻¹ (d) 2800ms⁻¹
Correct […]
A voltmeter of range 2 V and resistance 300Ω cannot be converted into ammeter of range
Options
(a) 1A (b) 1mA (c) 100mA (d) 10mA
Correct Answer:
1mA
Explanation:
Ig = (2 / […]
What is the Q-value of the reaction? ¹H+⁷Li → ⁴He+⁴He The atomic masses of ¹H,⁴He and ⁷Li are 1.0078254u, 4.0026034u and 7.016004u, respectively.
Options
(a) 17.35 MeV (b) 18.06 MeV (c) 177.35 MeV […]
The wavelength of first line of Balmer series is 6563Å. The wavelength of first line of Lyman series will be
Options
(a) 1215.4Å (b) 2500Å (c) 7500Å (d) 600Å
Correct Answer:
1215.4Å
Explanation:
λ(ʟyman) […]
The wavelength of Kα line in copper is 1.5Å. The ionisation energy of K electron in copper is
Options
(a) 11.2×10⁻¹⁷ J (b) 12.9×10⁻¹⁶ J (c) 1.7×10⁻¹⁵ J (d) 10×10⁻¹⁶ J
Correct Answer:
12.9×10⁻¹⁶ […]
An electric motor runs on DC source of emf 200 V and draws a current of 10 A. If the efficiency be 40%, then the resistance of armature is
Options
(a) 2Ω (b) […]
The half-life of radioactive element is 600 yr. The fraction of sample that would remain after 3000 yr is
Options
(a) (1/2) (b) (1/16) (c) (1/8) (d) (1/32)
Correct Answer:
(1/32)
Explanation:
No […]
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