A horizontal straight wire 10 m long extending from east to west is falling with a speed of 5.0 m s-1, at right angles to the horizontal component of the earth’s magnetic field, 0.30 \(\times\)10-4 Wb m-2 .
- What is the instantaneous value of the emf induced in the wire?
- What is the direction of the emf?
- Which end of the wire is at the higher electrical potential?
A horizontal straight wire 10 m long extending from east to west is falling with a speed of 5.0 m s-1, at right angles to the horizontal component of the earth’s magnetic field, 0.30 \(\times\)10-4 Wb m-2 .
- What is the instantaneous value of the emf induced in the wire?
- What is the direction of the emf?
- Which end of the wire is at the higher electrical potential?
Solution and Explanation
Length of the wire, I = 10 m
Falling speed of the wire, v = 5.0 m/s
Magnetic field strength, B = 0.3 x 10-4 Wb m-2
a. Emf induced in the wire, e = Blv
=0.3×10-4×5×10
=1.5×10-3 V
b. Using Fleming's right had rule, it can be inferred that the direction of the induced emf is from West to East.
c. The eastern end of the wire is at a higher potential.
Top Questions on Electromagnetic induction
- If $ \epsilon_0 $ denotes the permittivity of free space and $ \Phi_E $ is the flux of the electric field through the area bounded by the closed surface, then the dimension of $ \epsilon_0 \frac{d\Phi_E}{dt} $ are that of:
- JEE Main - 2025
- Physics
- Electromagnetic induction
- A coil has 100 turns, each of area \( 0.05 \, \text{m}^2 \) and total resistance \( 1.5 \, \Omega \). It is inserted at an instant in a magnetic field of \( 90 \, \text{mT} \), with its axis parallel to the field. The charge induced in the coil at that instant is:
- CBSE CLASS XII - 2025
- Physics
- Electromagnetic induction
- Which of the following devices is based on the principle of electromagnetic induction?
- Bihar Board XII - 2025
- Physics
- Electromagnetic induction
- State Lenz’s law. A rod MN of length \( L \) is rotated about an axis passing through its end M perpendicular to its length, with a constant angular velocity \( \omega \) in a uniform magnetic field \( \vec{B} \) parallel to the axis. Obtain an expression for emf induced between its ends.
- CBSE CLASS XII - 2025
- Physics
- Electromagnetic induction
- Which of the following statements is not correct for electromagnetic induction?
- CUET (UG) - 2025
- Physics
- Electromagnetic induction
Questions Asked in CBSE CLASS XII exam
A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:(i)} Express the distance \( y \) between the wall and foot of the ladder in terms of \( h \) and height \( x \) on the wall at a certain instant. Also, write an expression in terms of \( h \) and \( x \) for the area \( A \) of the right triangle, as seen from the side by an observer.
- CBSE CLASS XII - 2025
- Application of derivatives
- A charge \( -6 \mu C \) is placed at the center B of a semicircle of radius 5 cm, as shown in the figure. An equal and opposite charge is placed at point D at a distance of 10 cm from B. A charge \( +5 \mu C \) is moved from point ‘C’ to point ‘A’ along the circumference. Calculate the work done on the charge.
- CBSE CLASS XII - 2025
- Electrostatics
- Charlie’s desperate attempt to find the third level reflects his frustration with the modern world. Substantiate the above statement with evidence from the story. (The Third Level)
निम्नलिखित गद्यांश की सप्रसंग व्याख्या कीजिए :
‘‘पुर्ज़े खोलकर फिर ठीक करना उतना कठिन काम नहीं है, लोग सीखते भी हैं, सिखाते भी हैं, अनाड़ी के हाथ में चाहे घड़ी मत दो पर जो घड़ीसाज़ी का इम्तहान पास कर आया है उसे तो देखने दो । साथ ही यह भी समझा दो कि आपको स्वयं घड़ी देखना, साफ़ करना और सुधारना आता है कि नहीं । हमें तो धोखा होता है कि परदादा की घड़ी जेब में डाले फिरते हो, वह बंद हो गई है, तुम्हें न चाबी देना आता है न पुर्ज़े सुधारना तो भी दूसरों को हाथ नहीं लगाने देते इत्यादि ।’’
- CBSE CLASS XII - 2025
- सप्रसंग व्याख्या
- Draw the structure of the major monohalo product for each of the following reactions:
- CBSE CLASS XII - 2025
- Haloalkanes And Haloarenes
Concepts Used:
Faradays Laws of Induction
There are two laws, given by Faraday which explain the phenomena of electromagnetic induction:
Faraday's First Law:
Whenever a conductor is placed in a varying magnetic field, an emf is induced. If the conductor circuit is closed, a current is induced, known as the induced current.
Faraday's Second Law:
The Emf induced inside a coil is equal to the rate of change of associated magnetic flux.
This law can be mathematically written as:
∈\(-N {\triangle \phi \over \triangle t}\)
