Neco Model Questions Vol1 2017 Physics Question 40

Practice objective / multiple choice question 40 from the 2017 Neco Model Questions Vol1 Physics examination.

Neco Model Questions Vol1 2017 Physics Objective / Multiple Choice Hard Difficulty
Question 40 NECO_MODEL_QUESTIONS_VOL1 • 2017 • PHYSICS • objective

A rectangular coil of \(N=200\) turns and area \(A=0.01\ \text{m}^{2}\) rotates at a constant angular speed \(\omega=300\ \text{rad s}^{-1}\) in a uniform magnetic field of magnitude \(B=0.5\ \text{T}\). The coil is connected to a resistor of resistance \(R=10\ \Omega\). (i) Write the expression for the induced emf \(\varepsilon(t)\) as a function of time. (ii) Find the rms current in the circuit. (iii) Determine the average electrical power dissipated in the resistor. (iv) Calculate the mechanical torque that must be supplied to keep the coil rotating at the given speed.

Answer Options

A. Induced emf: \(\varepsilon(t)=250\sin(300 t)\) V; rms current = 18.0 A; average power = 3.2 kW; required torque = 12 N·m.
B. Induced emf: \(\varepsilon(t)=300\sin(250 t)\) V; rms current = 21.2 A; average power = 5.0 kW; required torque = 15 N·m.
C. Induced emf: \(\varepsilon(t)=300\sin(300 t)\) V; rms current = 25.0 A; average power = 4.5 kW; required torque = 18 N·m.
Correct Answer D. Induced emf: \(\varepsilon(t)=300\sin(300 t)\) V; rms current = 21.2 A; average power = 4.5 kW; required torque = 15 N·m.
Correct Answer
D
Correct Option:
Induced emf: \(\varepsilon(t)=300\sin(300 t)\) V; rms current = 21.2 A; average power = 4.5 kW; required torque = 15 N·m.

About This Question

This is Neco Model Questions Vol1 2017 Physics Question 40. It is one of the objective questions from the 2017 Neco Model Questions Vol1 Physics examination.

Difficulty level: Hard .

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