Reciprocal of impedance is

• susceptance

• conductance

• admittance

• transconductance

In  a  series LCR  circuit, the voltage across the resistance, capacitance and inductance is 10 V each. If the capacitance is  short  circuited  the voltage across the inductance will be

• 140 V

• 10 $\sqrt{2}$ V

• 10/ $\sqrt{2}$ V

• 20 V

In an electrical containing L, C and R which of the following does not denote the dimensions and frequency?

• LC

• $\frac{1}{\sqrt{\mathrm{L} \mathrm{C}}}$

• $\frac{1}{\mathrm{RC}}$

• $\frac{\mathrm{R}}{\mathrm{L}}$

If frequency of R-L circuit is f then impedance will be

• $\sqrt{{\mathrm{R}}^2 + {\left( 2\mathrm{\pi fL} \right)}^2}$

• R² + ( 2$\mathrm{\pi }$f² )²

• $\sqrt{\left( {\mathrm{R}}^2 + {\mathrm{L\pi f}}^2 \right)}$

• R² + (2$\mathrm{\pi }$f )²

155.

A bulb  and  a condenser are connected in with an A>C source. On increasibg the frequency will

• increase

• decrease

• sometimes increase and sometimes decrease

• neither increase nor decrease.

When 100 V d.c  is applied across a coil, a current of 1 A nows through it. When  100 V a.c. of 50 Hz is applied to the same coil only 0.5 A flows. The inductance of the coil is

• 0.55 H

• 5.5 H

• 0.55 mH

• 55 mH

Assertion:  The alternating current lags behind the e.m.f. by a phase angle of  $\mathrm{\pi }$/2, when AC flows through an inductor. 

Reason:  The inductive reactance increases as the frequency of AC source decreases.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

What is the dimensions of impedance ?

• [ M L² T^-3 A^-2 ]

• [ M^-1 L^-2 T³ A² ] 

• [ M L³ T^-3 A^-2 ]

• [ M^-1 L^-3 T³ A² ]

In an AC circuit the potential differences across an inductance and resistance joined in series are respectively 16 V and 20 V. The total potential difference of the source is

• 20.0 V

• 25.6 V

• 31.9 V

• 53.5 V

The focal length of the objective and eye lenses of a microscope are 1.6 cm and 2.5 cm respectively. The distance between the two lenses is 21. 7 cm. If the final image is formed at infinity. What is the linear magnification?

• 11

• 110

• 1.1

• 44