In an AC circuit, voltage V = V₀sinωt  and inductor L is connected across the circuit. Then the instantaneous power will be

• $\frac{{\mathrm{V}}_0^2}{2\mathrm{\omega L}} \mathrm{sin\omega t}$

• $\frac{- {\mathrm{V}}_0^2}{2\mathrm{\omega L}} \mathrm{sin\omega t}$

• $\frac{- {\mathrm{V}}_0^2}{2\mathrm{\omega L}} \sin 2\mathrm{\omega t}$

• $\frac{{\mathrm{V}}_0^2}{\mathrm{\omega L}}\sin 2\mathrm{\omega t}$

Two sinusoidal waves of intensity I having same frequency and same amplitude interferes constructively at a point. The resultant intensity at a point will be

• I

• 2I

• 4I

• 8I

In the given circuit, the voltage across the load is maintained at 12 V. The current in the zener diode varies from 0-50 mA. What is the maximum wattage of the diode?

• 12 W

• 6 W

• 0.6 W

• 1.2 W

A photon is incident having frequency 1 x 10 sec^-1. Threshold frequency of metal is 5 x 10¹³ sec^-1. Find the kinetic energy of the ejected electron.

• 3.3 × 10^-21 J

• 6.6 × 10^-21 J

• 3.3 × 10^-20 J

• 6.6 × 10^-20 J

In given series LCR circuit R = 4Ω, X_L = 5 Ω and X_C = 8Ω, the current

• Leads the voltage by tan^-1(3/4).

• Leads the voltage by tan^-1(5/8)

• Lags the voltage by tan^-1(3/4)

• Lags the voltage by tan^-1(5/8)

A wire of mass 100 g, length 1 m and current 5 A is balanced in mid air by a magnetic field B, then find the value of B

• 0.2 T

• 0.1 T

• 0.5 T

• 0.6 T

27.

A toroid with mean radius r₀, diameter 2a have turns carrying current I. What is the magnetic field B outside the toroid?

• $\frac{\mathrm{N} \mathrm{I}}{2{\mathrm{\pi r}}_0}$

• $\frac{\mathrm{NI}}{2\mathrm{\pi } \left({\mathrm{r}}_0 + \mathrm{a}\right)}$

• $\frac{\mathrm{NI}}{\mathrm{\pi }\left({\mathrm{r}}_0 + \mathrm{a}\right)}$

• zero

Identify incorrect for electric charge q

• quantised

• conserved

• additive

• non-transferable

Which of the following parameter in the series LCR circuit is analogous to driving force F(t) in mechanics?

• $\frac{{\mathrm{V}}_0}{\mathrm{L}}$

• inductance L

• capacitance C

• voltage V₀

The minimum magnetic dipole moment of electron in hydrogen atom is

• $\frac{\mathrm{eh}}{2\mathrm{\pi m}}$

• $\frac{\mathrm{eh}}{4\mathrm{\pi m}}$

• $\frac{\mathrm{eh}}{\mathrm{\pi m}}$

• 0