Related InterviewSolutions

• Specific heat of water is 4.2 J/g°C. If light of frequency 2 ×109 Hz is used to heat 500 gm of water from 30°C to 50°C, the number of photons needed will be1. 1.69 × 10292. 3.2 × 10283. 2.80 × 1044. 2.80 × 105
• De-Broglie wavelength of electron isλeand wavelength of the photon isλp. What is the relation betweenλeand λpif both have the same energy?1. \(\lambda_p \propto \sqrt \lambda_e\)2. \(\lambda_p \propto \lambda_e\)3. \(\lambda_p \propto \lambda_e^2\)4. \(\lambda_p \propto {1 \over \lambda_e}\)
• For photoelectric emission from certain metal the cut off frequency is v. If radiation of frequency 2v impinges onthe metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass):1. \(\sqrt{\dfrac{h\nu}{m}}\)2. \(\sqrt{\dfrac{2h\nu}{m}}\)3. \(2\sqrt{\dfrac{h\nu}{m}}\)4. \(\sqrt{\dfrac{h\nu}{2m}}\)
• In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energeticelectric electrons is 0.5 eV. The corresponding stopping potential is1. 2.3 V2. 1.8 V3. 1.3 V4. 0.5 V
• For a photoelectric emissionifλe&λpare wavelengths of electron and photon respectively having same energy E, then correct relationship among the following betweenλe&λp1. \(\lambda_p \propto \lambda_e\)2. \(\lambda_p \propto \dfrac{1}{\sqrt{\lambda_e}}\)3. \(\lambda^2_p \propto \lambda_e\)4. \(\lambda_p \propto \lambda_e^2\)
• For photoelectric emission from certain metal the cutoff frequency is v. If radiation of frequency 2 v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass):1. \(\sqrt {hv/(2m)}\)2. \(\sqrt {hv/m}\)3. \(\sqrt {2hv/m}\)4. \(2\sqrt {hv/m}\)
• If the kinetic energy of an electron gets doubled, its de Broglie wavelength will become _________.1. doubled2. (1/√2) times3. squared4. √2 times
• The mathematical form of Maxwell Boltzmann Law is1. \(n_i=\frac{g_i}{e^{\alpha+\beta\epsilon_i}-1}\)2. \(n_i=\frac{g_i}{e^{\alpha+\beta\epsilon_i}+1}\)3. \(n_i=\frac{g_i}{e^{\alpha+\beta\epsilon_i}}\)4. \(n_i=\frac{e^{\alpha+\beta\epsilon_i}}{g_i}\)
• 50 W/m2 energy density of sunlight is normally incident on the surface of a solar panel. Some part of incident energy (25%) is reflected from the surface and the rest is absorbed. The force exerted on 1m2 surface area will be close to (c = 3 × 108 m/s):1. 15 × 10-8 N2. 20 × 10 -8 N3. 10 × 10-8 N4. 35 × 10-8 N
• The type of electron emission whereina very strong electric field applied to the metal pulls the electrons out of the metal surface is called1. Thermionic emission2. Field emission3. Photoelectric emission4. None of the above