In Pakistan the electricity standards are:

• A) 20 Volts and 50 Hertz
• B) 30 Volts and 50 Hertz
• C) 230 Volts and 50 Hertz
• D) 10 Volts and 50 Hertz

A particular device transmitted a signal in the form of electromagnetic waves of frequency 7.5 * 108 Hz. What is the wavelength of the signal?

• A) 40 m
• B) 0.4 m
• C) 4.04 m
• D) 4.0 m

How is the capacitance of a capacitor defined as?

• A) Electric field strength
• B) Voltage per unit charge
• C) Amount of charge stored per unit potential difference
• D) Electric force per unit charge

Force on a charged particle is zero when projected at angle with the magnetic field:

• A) 0 degree
• B) 180 degree
• C) 270 degree
• D) 90 degree

A capacitor in an LC oscillator has a maximum potential difference of 15V and a maximum energy of 360 μJ. At a certain instant the energy in the capacitor is 40 μJ. At that instant what is the emf induced in the inductor?

• A) 15V
• B) zero
• C) 10V
• D) 5V

The total energy in an LC circuit is 5.0 × 10−6 J. If L = 25mH the maximum current is:

• A) 14mA
• B) 10mA
• C) 28mA
• D) 20mA

The product of resistance and capacitance is called

• A) Velocity
• B) force
• C) Current
• D) Time

What is the direction of the area vector for a flat surface in the context of magnetic flux?

• A) Perpendicular to the surface
• B) Tangential to the surface
• C) Directed randomly
• D) Parallel to the surface

An inductor may store energy in its:

• A) Magnetic field
• B) Electric field
• C) Potential field
• D) Gravitational field

If the current in a circuit is 2 A and the resistance is 3 Ω, what is the power consumed?

• A) 5 watts
• B) 12 watts
• C) 6 watts
• D) 18 watts

Total flux through a closed surface depends on:

• A) Medium only
• B) Charge and – N
• C) Charge enclosed
• D) Shape of surface

The number of turns becomes double, but length remain same, then magnetic field in the solenoid become

• A) Half
• B) Remain same
• C) Double
• D) Zero

What is the role of an EMF source, such as a battery, in an electrical circuit?

• A) To provide energy to the circuit
• B) To resist the flow of current
• C) To measure electrical potential
• D) To act as a short circuit

If a conductor is placed between the plates of a capacitor, what will happen to the potential difference between the plates?

• A) It will increase
• B) It will become zero
• C) It will be maintained
• D) It will decrease

Which one of the following is the velocity of a carrier wave?

• A) 3 × 109 ms-1
• B) 3 × 1010 ms-1
• C) 3 × 106 ms-1
• D) 3 × 108 ms-1

Work done on a charged particle moving in uniform magnetic field is:

• A) Negative
• B) Minimum
• C) Maximum
• D) Zero

The focal length of convex lens is:

• A) Negative
• B) Small
• C) Positive
• D) Large

One Tesla is equal to

• A) N /Am
• B) N /A m
• C) N A/m
• D) N A m

The reaction of an induction at 50 Hz is 10 Ω, its reactance at 100 Hz becomes:

• A) 2.5 Ω
• B) 20 Ω
• C) 5 Ω
• D) 1 Ω

In the context of a charged particle moving perpendicular to the magnetic field, If both the velocity (v) and the magnetic field strength (B) are doubled while keeping the charge (q) and mass (m) constant, what happens to the orbital radius (r)?

• A) No change in the orbital radius.
• B) Orbital radius quadruples.
• C) Orbital radius doubles.
• D) Orbital radius halves.