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What is curl of E for B = 15t?
15
−15
7.5
−7.5
−15
Given: The magnetic flux density B is given as 15t, where t is time.
The magnetic flux density B is given as 15t, where t is time.
∇×E=−∂t∂B
Identify Faraday's Law of Induction
Faraday's Law in differential form relates the curl of the electric field to the time rate of change of the magnetic flux density.
∇×E=−∂t∂B
Substitute the given magnetic field
We are given the magnetic flux density B=15t. We substitute this into the formula.
∇×E=−∂t∂(15t)
Perform the differentiation
Differentiate 15t with respect to time t. The derivative of 15t with respect to t is 15.
∇×E=−(15)=−15
B is correct because applying Faraday's Law, the curl of E is equal to the negative rate of change of B, which results in −15.
This concept is fundamental to the study of electromagnetic waves; always remember the negative sign, which represents Lenz's Law, ensuring energy conservation in inductive systems.