41.

Given,

R₁ = 10 Ω, C₁ = 2µF, R₂ = 20 and C₂ =  4F

The time constants (in µs) for the circuits I, II, III are respectively.

• 18, 18/9, 4

• 4, 8/9, 18

• 18, 4, 8/9

• 8/9, 18, 4

When a battery connected across a resistor of 16Ω, the voltage across the resistor is 12 V. When the same battery is connected across itt hen the voltage is 11 V. The internal
resistance of the battery (in ohm) is

• $\frac{10}{7}$

• $\frac{20}{7}$

• $\frac{25}{7}$

• $\frac{30}{7}$

The total current supplied to the given circuit is

• 9 A

• 6 A

• 2 A

• 4 A

In the given circuit, the AC source has ω = 100 rad/s, considering the inductor and capacitor to be ideal,

• the current through the circuit  is 0.4 A

• the current through the circuit is 0.3$\sqrt{2}$ A

• the voltage across 100 Ω  resistor is 10$\sqrt{2}$ V

• the voltage across 50 Ω resistor is 10 V

Which energy state of triply ionized beryllium Be³⁺ has the same orbital radius as that of ground state of hydrogen atom ?

• n = 8 state

• n = 5 state

• n = 4 state

• n = 2 state

In Bohr's model of hydrogen atom, the electron circulates around the nucleus in a path of radius 5 x 10^-11 m at a frequency of 6.8 x 10¹⁵ Hz. The value of magnetic field and equivalent magnetic moment will be

• 15.4 T and 8.9 x 10^-24 A-m²

• 13.4 T and 8.9 x 10^-24 A-m²

• 18.4 T and 9.8 x 10^-24 A-m²

• 13.4 T and 9.8 x 10^-24 A-m²

In β⁺ decay process, which of the following changes takes place inside the nucleus

• ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X} \to {}_{\mathrm{Z}+1}{}^{\mathrm{A}}\mathrm{Y} + {\mathrm{e}}^{+} + \mathrm{v}$

• ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X} \to {}_{\mathrm{Z}+1}{}^{\mathrm{A}}\mathrm{Y} + {\mathrm{e}}^{-} + \stackrel{-}{\mathrm{v}}$

• ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X} \to {}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{Y} + {\mathrm{e}}^{-} + \mathrm{v}$

• ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X} \to {}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{Y} + {\mathrm{e}}^{-} + \stackrel{-}{\mathrm{v}}$

A p-n-p transistor is used in common-emitter mode in an amplifier circuit. A change of 45 µA in the base current brings a change of 3 mA in collector current and 0.05 V in base-emitter voltage. If a load of 7 kΩ is used, then voltage gain of amplifier is

• 729.25

• 824.41

• 236.34

• 424.27

The radius of curvature of a concave mirror, measured by a spherometer is given by $\mathrm{R} = \frac{{\mathrm{l}}^2}{6\mathrm{h}} + \frac{\mathrm{h}}{2}$. The value of l and h are 4.0 cm and 0.065 cm respectively, where l is measured by a meter scale and h by a spherometer. The relative error in the measurement of R is

• 0.06

• 0.6

• 0.023

• 2.3

Light of wavelength λ , strikes a photoelectric surface and electrons are ejected with an energy E. If E is to be increased to exactly twice its original value, the wavelength changes to λ', where

• $\mathrm{\lambda }\text{'} \mathrm{is} \mathrm{less} \mathrm{than} \frac{\mathrm{\lambda }}{2}$

• $\mathrm{\lambda }\text{'} \mathrm{is} \mathrm{greater} \mathrm{than} \frac{\mathrm{\lambda }}{2}$

• $\mathrm{\lambda }\text{'} \mathrm{is} \mathrm{greater} \mathrm{than} \frac{\mathrm{\lambda }}{2} \mathrm{but} \mathrm{less} \mathrm{than} \mathrm{\lambda }$

• $\mathrm{\lambda }\text{'} \mathrm{is} \mathrm{exactly} \mathrm{equal} \mathrm{to} \frac{\mathrm{\lambda }}{2}$