Exams › NEET › Physics

The peak value of an alternating e.m.f. is 10 V and its frequency is 50 Hz. At time \(t = \frac{1}{600}\) s, the instantaneous e.m.f. is

1. 10 V
2. \(5\sqrt{3}\) V
3. 5 V
4. 1 V

Correct answer: \(5\sqrt{3}\) V

Solution

The emf is \(E = E_0\cos(\omega t)\), where \(E_0 = 10\) V and \(\omega = 2\pi f = 100\pi\) rad/s. At \(t = 1/600\) s, \(\omega t = 100\pi/600 = \pi/6\), so \(E = 10\cos(\pi/6) = 10\cdot \sqrt{3}/2 = 5\sqrt{3}\) V.

Related NEET Physics questions

• The current flowing through the resistor in a series LCR a.c. circuit, is I=ε / R Now the inductor and capacitor are connected in parallel and joined in series with the resistor as shown in figure. The current in the circuit is now. (Symbols have their usual meaning)
• Which of the following will not increase voltage in a simple generator?
• With increase in frequency of an A.C. supply, the inductive reactance
• ln an A C circuit, the instantanceous emf and current are given by e=100 sin 30 t, i=sin (30 t (π)/(4)) In one cycle of A C, the average power consumed by the circuit and the wattles current are, respectively
• The Joules heating effect for an electric heater in A. C and in D.C. circuit is
• A resistance (R)=12 Ω; inductance (L)=2 henry and capacitive reactance C=5 m F are connected in series to an ac generator, then:

⚔️ Practice NEET Physics free + battle 1v1 →