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WorksheetsFIVIZZ: ROAD TO MIDSEM - PHYSICS 3
Total questions: 20
Worksheet time: 25mins
A monochromatic light of frequency 4fo is directed to the photocell that consists of material with threshold frequency, fo. Find its stopping potential.
5hfo/e
5hfo
3hfo
3hfo/e
The work function of a metal is 1.3 eV. The stopping potential for a photoelectron emitted from the metal by an incident photon with frequency 7.0 x 1014Hz.
1 x 1019 V
1.6 x 1019 V
1.6 V
1.0 V
Figure 1 shows a graph of In N against t for a sample of radioactive substance, where N is the number of radioactive atoms in the sample after t minutes. Find the half-life of the radioactive substance.
75 s
75 min
924 s
924 min
Calculate the mass defect of Fluorine-19 nucleus with a proton number of 9.
[Mass of neutron, mn = 1.00867 u; mass of proton, mp= 1.00783 u; mass of fluorine nucleus, mF= 18.99840 u]
0.16687
0.15877
0.15793
9.22840
The half-life of radium is 1600 years. If the mass of sample of radium is 1.00 g, what is the number of nuclei that decays in 1 s?
[Molar mass of radium= 226 g mol·1, 1 year= 365 days]
3.65 x 1010
1.15 x 1018
2.66 x 1021
3.15 x 1015
A -8.9nC charge is held 70cm away from a +0.3nC charge. What is the electrostatic force between the two charges?
3.43 x 10-8N, attractive
4.9 x 10-8N, repulsive
4.9x 10-8N, attractive
3.43 x 10-8N, repulsive
An electron is moving in the presence of an electric field of 329 N C-1. Determine the magnitude of force acting on the electron.
5.38 x 10-17N
2.06 x 10-21N
2.06 x 1021N
5.26 x 10-17N
A charge of magnitude 3.8µC, is placed at the center of a sphere. Determine the electric flux at the surface of the sphere.
3.42 x 104N m2 C-1
4.22 x 10-16N m2 C-1
4.29 x 105N m2 C-1
2.33 x 10-6N m2 C-1
What is the field strength if charge 7.2 μC experiences a 0.10N force?
1.389 x 104N C-1
7.2 x 10-7N C-1
1.389 x 10-6N C-1
7.2 x 105N C-1
The number of electric field lines passing through a given area represents the
charge density
field direction
charge motion
electric flux
Three capacitors of 5.0 μF, 1.5 μF, and 3.0 μF are connected in series. Find the combined capacitance.
9.5 μF
1.2 μF
0.83 μF
8.7 μF
An aluminium wire is 3.2 cm long and 12 mm in a diameter, what is its resistance given that its resistivity is 2.82 x 10-8Ωm.
7.98 x 10-6 Ω
7.98 x 10-4 Ω
1.99 x 10-6 Ω
1.99 x 10-4 Ω
A current of 7.5 A flows through a copper wire of diameter 0.44 mm when it is connected to a potential difference of 30 V. How long is the wire?
[Resistivity of copper = 1. 7 x 10-8 Ω m]
35.78 x 106 m
35.78 m
143.11 m
71.55 x 106 m
Kirchhoff's Rule states that
the total current entering a junction is exactly equal to the total current leaving the same junction
the sum of the currents at any junction is zero
the sum of voltage rises must be equal to the sum of voltage drops around a closed loop
the sum of the potential differences across all the elements around any closed-circuit loop must not be zero
The current in a 120V lamp is 3.4 A. If the cost of electrical energy is RM 0.075 per kilowatt hour, how much does it cost to operate the light for an hour?
RM 0.031
RM 30.60
RM 0.002
RM 5.44
The current in elements of an A.C circuit is independent of the frequency at any given voltages. Which element(s) behave as such?
combination of inductors and capacitors
resistors only
capacitors only
inductors only
A 275 Ω resistor is connected across an A.C voltage source V(t) = 138sin120πt. What is the average power delivered to this circuit?
69.25 W
34.62 W
0.35 W
16.85 W
Calculate the reactance of an inductor of 21mH at a frequency of 75 Hz.
0.10 x 10-3 Ω
0.10 Ω
9.90 x 10-3 Ω
9.90 Ω
An R-L-C series circuit is connected to a 110 V A.C line. Given R = 9.0 Ω, XL =28 Ω and XC = 16 Ω, compute the impedance of the circuit and the phase angle between the current and voltage.
15Ω, voltage leads by 53.13°
15Ω, voltage lags by 53.13°
15Ω, voltage leads by 36.87°
15, voltage lags by 36.87°
If the instantaneous current is given by I(t)= 4cos (ωt+ϕ)A, then the rms value of current is
4 A
2√2 A
4√2 A
0 A
