Modern Physics

Q. If A = 0 and B = 1, what is the output of the XOR gate?
  • A. 0
  • B. 1
  • C. 2
  • D. Undefined
Q. If A = 1 and B = 1, what is the output of the AND gate?
  • A. 0
  • B. 1
  • C. 2
  • D. Undefined
Q. If A = 1, B = 1, and C = 0, what is the output of A OR (B AND C)?
  • A. 0
  • B. 1
  • C. 2
  • D. Undefined
Q. If A = 1, B = 1, and C = 0, what is the output of the expression (A OR B) AND C?
  • A. 0
  • B. 1
  • C. 2
  • D. 3
Q. If a metal has a work function of 2 eV, what is the minimum wavelength of light required to cause the photoelectric effect?
  • A. 620 nm
  • B. 310 nm
  • C. 1240 nm
  • D. 500 nm
Q. If a metal has a work function of 2 eV, what is the threshold wavelength for the photoelectric effect?
  • A. 620 nm
  • B. 400 nm
  • C. 500 nm
  • D. 300 nm
Q. If a metal has a work function of 2.0 eV, what is the maximum kinetic energy of the emitted electrons when illuminated with light of 5.0 eV energy?
  • A. 3.0 eV
  • B. 2.0 eV
  • C. 5.0 eV
  • D. 0 eV
Q. If a metal has a work function of 4 eV, what is the threshold frequency for the photoelectric effect?
  • A. 1.5 x 10^14 Hz
  • B. 3.2 x 10^14 Hz
  • C. 5.0 x 10^14 Hz
  • D. 6.3 x 10^14 Hz
Q. If the frequency of incident light is doubled, what happens to the kinetic energy of the emitted electrons?
  • A. It remains the same
  • B. It doubles
  • C. It quadruples
  • D. It decreases
Q. If the intensity of light is doubled while keeping the frequency constant, what happens to the number of emitted electrons?
  • A. It doubles
  • B. It remains the same
  • C. It is halved
  • D. It becomes zero
Q. If the intensity of light is doubled while keeping the frequency constant, what happens to the number of emitted electrons in the photoelectric effect?
  • A. It doubles
  • B. It remains the same
  • C. It is halved
  • D. It becomes zero
Q. If the work function of a metal is 4.5 eV, what is the threshold wavelength for the photoelectric effect?
  • A. 400 nm
  • B. 500 nm
  • C. 600 nm
  • D. 700 nm
Q. In a circuit with two inputs A and B, if A = 0 and B = 0, what is the output of an OR gate?
  • A. 0
  • B. 1
  • C. 2
  • D. 3
Q. In a communication system, what does 'noise' refer to?
  • A. The desired signal
  • B. Unwanted disturbances that affect the signal
  • C. The modulation technique used
  • D. The bandwidth of the channel
Q. In a communication system, what does 'signal-to-noise ratio' (SNR) measure?
  • A. The strength of the signal relative to background noise
  • B. The total power of the signal
  • C. The bandwidth of the communication channel
  • D. The efficiency of the modulation technique
Q. In a digital communication system, what does the term 'bit rate' refer to?
  • A. The number of bits transmitted per second
  • B. The number of bits stored in a device
  • C. The frequency of the carrier wave
  • D. The duration of each bit
Q. In a hydrogen atom, the energy levels are quantized. What is the formula for the energy of the nth level?
  • A. E_n = -13.6/n^2 eV
  • B. E_n = -13.6n^2 eV
  • C. E_n = -13.6/n eV
  • D. E_n = -13.6n eV
Q. In a hydrogen atom, what is the energy of the electron in the ground state?
  • A. -13.6 eV
  • B. -3.4 eV
  • C. -1.51 eV
  • D. 0 eV
Q. In a hydrogen atom, what is the energy of the electron in the n=2 state?
  • A. -3.4 eV
  • B. -13.6 eV
  • C. -1.51 eV
  • D. -0.85 eV
Q. In a hydrogen atom, which transition emits the photon with the highest energy?
  • A. n=2 to n=1
  • B. n=3 to n=2
  • C. n=4 to n=3
  • D. n=5 to n=4
Q. In a hydrogen atom, which transition would emit the highest energy photon?
  • A. n=2 to n=1
  • B. n=3 to n=2
  • C. n=4 to n=3
  • D. n=5 to n=4
Q. In a hydrogen atom, which transition would emit the photon with the highest energy?
  • A. n=2 to n=1
  • B. n=3 to n=2
  • C. n=4 to n=3
  • D. n=5 to n=4
Q. In a nuclear reaction, what is conserved?
  • A. Mass only
  • B. Charge only
  • C. Mass and charge
  • D. Energy only
Q. In a nuclear reaction, what is the term for the energy released when a nucleus is formed from its constituent nucleons?
  • A. Binding energy
  • B. Kinetic energy
  • C. Potential energy
  • D. Thermal energy
Q. In a nuclear reaction, what is the term for the mass difference between the reactants and products?
  • A. Mass defect
  • B. Binding energy
  • C. Nuclear fusion
  • D. Nuclear fission
Q. In a p-n junction diode, what happens when it is forward biased?
  • A. Depletion region widens
  • B. Current flows easily
  • C. No current flows
  • D. Reverse breakdown occurs
Q. In a p-n junction diode, what happens when it is reverse-biased?
  • A. Current flows freely
  • B. Depletion region widens
  • C. Holes move towards the n-side
  • D. Electrons move towards the p-side
Q. In a p-n junction, what is formed at the junction region?
  • A. Electric field
  • B. Magnetic field
  • C. Thermal field
  • D. Gravitational field
Q. In a p-n junction, what is the region called where no charge carriers are present?
  • A. Depletion region
  • B. Conduction band
  • C. Valence band
  • D. Neutral zone
Q. In a p-n junction, what is the region called where no charge carriers exist?
  • A. Depletion region
  • B. Conduction band
  • C. Valence band
  • D. Neutral zone
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