C and Si both have same lattice strcture, having 4 bonding electron in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because:
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(a) In case of V the […]
Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a phototsensitive material. he stopping potential is measured to be 3.57 V. The threshold frequency of the materials […]
A 200 W sodium street lamp emits yellow light of wavelength 0.6 µm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per […]
If voltage across a bulb rated 220 volt-100 Watt drops by 2.5% of its rated value, the percentage of the rated value by which the power would decrease is:
Options
(a) 20% (b) […]
If the number of radius of ²⁷Al is 3.6 Fermi, the approximate nuclear radius of ⁶⁴Cu in Fermi is:
Options
(a) 2.4 (b) 1.2 (c) 4.8 (d) 3.6
Correct Answer:
4.8
Explanation:
The […]
Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths λ₁:λ₂ emitted in the two cases […]
An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be: (m is the mass […]
In an electrical circuit R,L,C and an AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and the current in the circuit is […]
An α-particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of 0.25 Wb m⁻². The de-Broglie wavelength associated with the particle will be
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(a) […]
Two spheres A and B of masses m1 and m2 respectively collide. A is at rest initially and B is moving with velocity v along x-axis. After collision B has a velocity v/2 in a […]
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