Which of the following devices does NOT make use of current carrying conductor in a magnetic field?

Question

Examoogle · Accepted Answer

The correct answer is Option D: Electric heater. An electric heater does not make use of a current-carrying conductor in a magnetic field. Instead, it operates on the principle of the heating effect of electric current (Joule heating), where electrical energy is converted directly into heat energy through a high-resistance wire (heating element) without requiring any magnetic field.

Step-by-Step Solution & Concepts:
An electric heater does not make use of a current-carrying conductor in a magnetic field. Instead, it operates on the principle of the heating effect of electric current (Joule heating), where electrical energy is converted directly into heat energy through a high-resistance wire (heating element) without requiring any magnetic field.

Working Principle: When an electric current passes through a conductor with high electrical resistance (such as nichrome wire in an electric heater), electrical energy is dissipated as thermal energy due to collisions between free electrons and the vibrating metal lattice ions (Joule's Law of Heating, $H = I^2Rt$). Devices like electric motors, electric fans, and electric generators rely directly on electromagnetic induction or the magnetic force on a current-carrying conductor (Lorentz force, $F = I(\vec{L} 	imes \vec{B})$).

Key Formulas: $H = I^2 R t$ — Joule's law of heating; $\vec{F} = I(\vec{L} 	imes \vec{B})$ — Magnetic force on a current-carrying conductor; $\varepsilon = -\frac{d\Phi_B}{dt}$ — Faraday's law of electromagnetic induction

Key Points: An electric motor and electric fan convert electrical energy into mechanical work using the magnetic force on current-carrying coils.; An electric generator converts mechanical energy into electrical energy using electromagnetic induction.; An electric heater utilizes the heating effect of electric current, passing current through a high resistance wire (like nichrome) without requiring magnets.

Advantages: Joule heating provides immediate, direct, and efficient conversion of electrical energy into thermal energy.

Disadvantages: Resistive heating devices do not produce rotational motion or magnetic fields.

Applications: Room heaters, water geysers, toasters, and electric irons.

Additional Info: Nichrome alloy (Nickel and Chromium) is commonly used as the heating element because of its high resistivity and high melting point.

Answer: D is correct — Electric heater does not make use of a current carrying conductor in a magnetic field; instead, it works on the heating effect of electric current (Joule heating).

Exam Tip: Always differentiate between devices based on electromagnetism (motors, generators, galvanometers) and thermal/resistive effects (heaters, fuses, incandescent bulbs).

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Discussion (0)

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Discussion (0)

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Related Questions

Discussion (0)

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Related Questions

Discussion (0)