TOPIC: ALTERNATING CURRENT
DIRECTION: Choose the correct answer from the lettered options.
1. The peak voltage in an r.m.s. circuit is 2.0V and the resistance of the circuit is 3.0Ω. Find
the peak current flowing.
A. 0.666A.
B. 1.5A.
C. 2.43A.
D. 1.333A.
The correct answer is option [A].
Hint: Io = Vo/R.
2. In the circuit transistor diagram shown, the terminals P, Q and R represent __________.
A. BASE, EMITTER, COLLECTOR
B. BASE, COLLECTOR, EMITTER
C. EMITTER, BASE, COLLECTOR
D. COLLECTOR, EMITTER, BASE
The correct answer is option [C].
3. The resistance in a series R-C circuit is 5W. If the impedance of the circuit is 13 Ω,
calculate the reactance of the capacitor.
A. 18Ω
B. 16 Ω
C. 14 Ω
4. An RLC circuit with R = 60Ω, L = 0.2H, C = 40mF and f = 392.86Hz experiences the
passage of an a.c. with peak value 0.1A. Obtain the value of the current vector, VC.
A. 10.0V.
B. 15.0V.
C. 18.4V.
D. 12.0V.
The correct answer is option [A].
Hint: VC = Io × XC = 0.1 × 100 = 10.0V.
5. Which of the following diagram represents correctly an n-p-n transistor?
A.
B.
C.
D. 12 Ω
TOPIC: ELEMENTARY MODERN PHYSICS
DIRECTION: Choose the correct answer from the lettered options.
1. Find the half-life of radio-isotope which has a decay constant 0.000456.
A. 1520 days.
B. 1248 days.
C. 2560 days.
D. 1452 days.
The correct answer is option [A].
Using the equation T½ = 0.693/λ
where λ = 0.000456/day, therefore, T½ = 0.693/0.000456days ≈ 1520days.
2. Which of the following is the correct definition of half-life?
A. The average life-time of a radioactive material
B. The time it takes a radioactive material to decay to half of its original quantity
C. Half the period of a radioactive material decays completely
D. Half of the decay constant
The correct answer is option [B].
3. In the equation of the Heisenberg uncertainty principle ΔX × ΔV ≥ h⁄m where h = plank
constant, m = mass of the particle, X = particle positron, V = particle velocity.
ΔX means what?
A. Displacement.
B. Particle positron.
C. Particle constancy.
D. Particle uncertainty.
The correct answer is option [D].
4. What is the decay constant of a radioactive element whose half-life is 3seconds?
A. 0.132s-1
B. 0.231s-1
C. 0.347s-1
D. 0.693s-1
ELEMENTARY MODERN PHYSICS
5. Uranium isotopes have the same ________.
A. nucleon number
B. number of neutrons
C. decay rate
D. proton number
The correct answer is option [D].
6. The work function of sodium is 2eV. Calculate the incident photon energy when sodium is
illuminated by a radiation of 1.5 x 10-10m wavelength.
[h = 6.63 x 10-34Js, 1eV = 1.6 x 10-19C, me = 9.1 x 10-31kg, c = 3 x 108m/s].
A. 13 x 10-18J.
B. 13.2 x 10-19J.
C. 13.2 x 10eV.
D. 4.3 x 10-33J.
The correct answer is option [B].
Hint: Incident photon energy = hf.
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