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Worksheets774 OGUN STATE FINALS PHYSICS
Total questions: 20
Worksheet time: 10mins
A 6 µF capacitor is connected to an AC supply of rms voltage 45 V. If a current of 0.45 A passes through, what is the frequency?
2.65×102 Hz
1.33 × 102 Hz
5.31×102 Hz
1.06×102 Hz
A coil is connected across 250 V, 50 Hz AC supply, with a current of 2.5 A passing through and power rated as 400 W. What is the power factor?
0.64
0.78
0.81
A voltage source 400 V is connected across 3 µF and 6 µF capacitors in series. What is energy stored in the 3 µF capacitor?
7.5×10−2J
10.67 × 10−2 J
2.56×10−2J
5.87 \times 10^{-2} J
Which of the following best states Lenz's Law?
The direction of induced current opposes the cause producing it
Induced current flows to aid the change in magnetic flux
Magnetic flux always increases in a closed loop
The direction of current is always clockwise in a coil
Net electric field at midpoint along axis of dipole is not zero for:
Same charges
Opposite charges
In an LC circuit, an inductor of 5 mH is connected in parallel with a capacitor of 50 μF. Find the natural frequency of oscillation.
10 Hz
50 Hz
100.7 Hz
318.3 Hz
A capacitor of 200 μF is connected to a source of Vrms = 120 V. If the capacitive reactance, what is the frequency of the AC source?
33.3 Hz
39.8 Hz
50.0 Hz
59.7 Hz
A circuit contains a resistor of resistance R = 8 ohms and an inductor with inductive reactance X L = 8 ohms. What is the total impedance Z of the circuit?
8 Ω
16 Ω
11.3 Ω
10 Ω
If the distance between two charges is doubled and the charges are kept constant, what happens to the force between them?
It doubles
It becomes half
It becomes one-fourth
It remains the same
If the distance between two charges is doubled, what happens to the electric potential energy between them?
It doubles
It becomes half
It becomes one-fourth
It remains the same
A galvanometer with a full-scale deflection current of I_g = 25 mA and internal resistance R_g = 0.5 Ω is to measure a current of I = 2.5 A. What is the value of the required shunt resistance R_s to convert it into an ammeter?
0.157Ω
0.01Ω
0.005Ω
0.25Ω
The direction of the electric field created by a negative charge is...
Outwards
Towards charge
Either outwards or towards charge
Calculate the magnitude of the force experienced by a current carrying wire of length 200 cm and current 2.0 A placed in a magnetic field of 0.5 T if the field is perpendicular to the wire.
2N
1N
5N
10N
Which law states that the sum of potential difference in a closed loop is zero.
Ohm’s law
Kirchhoff’s law
None of the above
Circuital law
A pair of equal but opposite charges separated by a distance is called?
Electric field
Magnetic dipole
Electric dipole
Polarization
Calculate the force of the magnetic field, given B = 5T, I = 100cm, I = 4A, θ = 30°.
10 N
5 N
8.66 N
20 N
A force q on another charge Q is represented by which formula?
F=r2qQ
F=qQ×r2
F=q+rQ
F=q−rQ
Kirchhoff’s current law states?
Sum of currents entering a junction equals sum of currents leaving
Voltage is directly proportional to current
Force is equal to mass times acceleration
Charge is conserved in a circuit
The law that gives the magnetic field generated by a constant electric current is?
Ampere’s law
Coulomb’s law
Biot-Savart law
Ohm’s law
A rectangular coil with 200 turns and an area of 240cm2 rotates in a uniform magnetic field of 0.15T. If the coil carries a current of 2.5A and rotates with an angular velocity of 850rpm, what is the instantaneous torque on the coil at t = 10s?
-1.87 Nm
-1.74 Nm
-1.63 Nm
