What is the energy, in electron-volts, of a photon of wavelength 500 nm (h = 6.63 × 10⁻³⁴ J s, c = 3.0 × 10⁸ m/s, e = 1.6 × 10⁻¹⁹ C)?
Correct answer B. 2.49 eV
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MDCAT ECAT Physics MCQs
Page 5 of MDCAT ECAT Physics multiple-choice questions with answers. Tap an option to check yourself.
Page 5 of 24
- Electromagnetic Induction 30
- Fluid Dynamics 30
- Electrostatics 30
- Electronics 30
- Electromagnetism 30
- Current Electricity 30
- Work and Energy 30
- Waves 30
- Vectors and Equilibrium 30
- Nuclear Physics 30
- Dawn of Modern Physics 30
- Thermodynamics 30
- Rotational and Circular Motion 30
- Atomic Spectra 30
- Alternating Current 30
- Force and Motion 30
The energy of a photon is directly proportional to its ____
Correct answer C. frequency
What is the rest mass of a photon?
Correct answer C. Zero
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What is the SI unit of Planck’s constant?
Correct answer B. J s
Which of the following radiations has the greatest energy per photon?
Correct answer C. X-rays
If the wavelength of light is doubled, what happens to the energy of each photon?
Correct answer A. It halves
The intensity of monochromatic light is increased while its frequency is kept constant. What changes?
Correct answer D. The number of photons arriving per second increases
In the photoelectric effect, the maximum kinetic energy of the emitted electrons depends on ____
Correct answer B. the frequency of the incident light
What is meant by the threshold frequency of a metal surface?
Correct answer D. The minimum frequency of light that can eject electrons from it
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The work function of a metal is the ____
Correct answer C. minimum energy needed to remove an electron from its surface
An ideal diode is reverse biased in series with a 1.0 kΩ resistor across a 10 V battery. What is the potential difference across the resistor?
Correct answer A. Approximately 0 V
A full-wave rectifier is fed from 50 Hz mains. What is the frequency of the ripple in its output?
Correct answer B. 100 Hz
A bridge rectifier uses silicon diodes (0.7 V each) and its transformer secondary gives 12 V rms. What is the approximate peak output voltage across the load?
Correct answer B. 15.6 V
A forward-biased silicon diode (0.7 V drop) is connected in series with a 430 Ω resistor across a 5.0 V supply. What current flows?
Correct answer B. 10 mA
A germanium diode (0.3 V drop) and a resistor are connected in series across a 9.0 V battery so that 20 mA flows in forward bias. What is the resistance?
Correct answer D. 435 Ω
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In a centre-tapped full-wave rectifier, each half of the secondary winding has a peak voltage of 15 V. What peak inverse voltage must each ideal diode withstand?
Correct answer D. 30 V
A full-wave rectifier is fed from a 60 Hz supply. How many output pulses are produced each second?
Correct answer B. 120
Two silicon diodes (0.7 V each) are connected in series, both forward biased, with a 230 Ω resistor across a 3.0 V supply. What is the current?
Correct answer D. 7.0 mA
A 1:10 step-down transformer connected to 230 V rms mains feeds an ideal half-wave rectifier. What is the peak output voltage?
Correct answer B. 32.5 V
An ideal half-wave rectifier gives output pulses of peak value 31.4 V. What is the average (DC) value of the output (Average = V₀/π)?
Correct answer C. 10.0 V