The variation of magnetic flux linked with a coil with time t is described as follows: the flux increases linearly from 0 to 10 Wb in the time interval t=0 to t=2 s . It then remains constant at 10 Wb from t=2 s to t=4 s , and finally decreases linearly to zero from t=4 s to t=5 s . The ratio of the magnitude of induced emf in the coil during the interval t=0 to 2 s to that during the interval t=4 s to 5 s is:

Step-by-step solution

According to Faraday's law of electromagnetic induction, the magnitude of the induced emf is given by |e| = | t | , which represents the absolute value of the slope of the flux-time graph. For the first interval ( t=0 to t=2 s ): Initial flux, ₁ = 0 Final flux, ₂ = 10 Wb Magnitude of induced emf, |e₁| = | 10 - 0 2 - 0 | = 5 V For the third interval ( t=4 s to t=5 s ): Initial flux, ₁ = 10 Wb Final flux, ₂ = 0 Magnitude of induced emf, |e₂| = | 0 - 10 5 - 4 | = 10 V The required ratio is |e₁| : |e₂| = 5 : 10 = 1:2 .