Recent questions tagged additional

A broad cast AM transmitter radiates $50 \;kw$ of carrier power . What will be the radiated power at $85 \%$ modulation ?

asked Oct 3, 2016 by meena.p

1 answer

A T.V tower has a height of 100 m , How much population is covered by the T.V broad cast if the average population density around the town is $5000 \;km^{-2}$?

asked Oct 3, 2016 by meena.p

1 answer

Out of the following which is not an essential element of a communication system ?

asked Sep 30, 2016 by meena.p

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A repeater is a combination of

asked Sep 30, 2016 by meena.p

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Line of sight propagation is

asked Sep 30, 2016 by meena.p

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Sky wave propagation is also called

asked Sep 30, 2016 by meena.p

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A coil has an inductance of $5\;H$ and resistance $20\; \Omega$ . An emf of $100\; v$ is applied to it. What is the energy stored in the magnetic field, when the current has reached its final value .

asked Sep 28, 2016 by meena.p

1 answer

What is the peak value of $220\;v\;a.c$

asked Sep 28, 2016 by meena.p

1 answer

In a series LCR circuit , the voltage across an inductor, a capacitor and a resistor are $30\;v, 30\;v$ and $60\;v$ respectively . What is the phase difference between the applied voltage and the current in the circuit .

asked Sep 28, 2016 by meena.p

1 answer

In an a.c circuit , there is no power consumption in an ideal inductor . why ?

asked Sep 28, 2016 by meena.p

1 answer

A resistor of resistance $100 \Omega$ is connected to an ac source. $E= (12 v) \sin (250 \pi s^{-1})t$ Find the energy dissipated as heat during $t=0$ to $t= 1.0\;ms$

asked Sep 28, 2016 by meena.p

1 answer

An electric motor operation on a $50\;v$ d.c supply draws a current of $12\;A$ . If the efficiency of the motor is $30\%$ , estimate the resistance of the motor .

asked Sep 28, 2016 by meena.p

1 answer

A generator develops am e.m.f of $120\;v$ and has a terminal potential difference of $115\;v$ when the as mature current is $25\;A$ What is the resistance of the as mature ?

asked Sep 28, 2016 by meena.p

1 answer

Can a capacitor be used instead of a choke coil in controlling a.c ?

asked Sep 28, 2016 by meena.p

1 answer

Why do we prefer a choke coil to a rheostat in controlling a.c ?

asked Sep 27, 2016 by meena.p

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Why are air cored chokes used for reduced high frequency a.c ?

asked Sep 27, 2016 by meena.p

1 answer

The calculate the current drawn by the prime of a transformer which steps down $200\;v$ to $20\;v$ to operate a device of resistance $20 \Omega$ the efficiency of the transformer to be $80\%$

asked Sep 27, 2016 by meena.p

1 answer

A transformer has an efficiency of $80\%$ and works at 100 volt and 4 kw. If the secondary voltage is $240\;volt$ calculate the primary and secondary currents

asked Sep 27, 2016 by meena.p

1 answer

A transformer has 50 turns in the primary and 100 in the secondary . If the primary is connected to a $220\;v$ d.c supply . What will be the voltage across the secondary ?

asked Sep 27, 2016 by meena.p

1 answer

A 20 V , 750 Hz source is connected to a series combination of $R= 100\; \Omega, C= 10 \mu F $ and $L= 0.1803\;H$ . Calculate the time in which resistance will get heated by $10^{\circ}$ if thermal capacity of the material $=25 \%$

asked Sep 27, 2016 by meena.p

1 answer

Two different coils have self inductance $L_1=8\;mH$ and $L_2=2\;mH$. At a certain instant , the current in the two coils is increasing at the same constant rate and the power supplied to the two coils is the same . Find the ratio of the current and energy stored.

asked Sep 27, 2016 by meena.p

1 answer

Find the wave length of EM wave of frequency $ 6 \times 10^{12}\;Hz$ in free space .

asked Aug 22, 2016 by meena.p

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A light have a wavelength of $6000^{\circ} A $ What is the energy of this light

asked Aug 22, 2016 by meena.p

1 answer

give relation with the E.M waves travel?

asked Aug 22, 2016 by meena.p

1 answer

In a plane electro magnetic wave the electric field oscillates simultaneously at a frequency $3 \times 10^{10} Hz $ and amplitude $50\;v/m$ what is the wave length of the wave

asked Aug 22, 2016 by meena.p

1 answer

A plane electro magnetic wave of frequency $25\;MHz$ travels in free space along the x- direction At a particular point in space and time the electric vector $\overrightarrow{E}= 6.3 v/m \hat j$. calculate $\overrightarrow{B}$ at this point .

asked Aug 22, 2016 by meena.p

1 answer

An E.m wave with poynting vector $6\;walt/m^2$ absorbed by a surface of area $12\;m^2$ Find the force on the surface .

asked Aug 22, 2016 by meena.p

1 answer

The binding energy of deuteron is $2.2 \;Mev$ and that of $_2He^4$ in $28\;Mev$ . If two deuterons are fused to form one $_2He^4$, then the energy released is

asked Aug 16, 2016 by meena.p

1 answer

A radioactive substance decays to $ \large\frac{1}{16}$ of its initial activity in 40 days . The half life of the radio active substance expressed in days is

asked Aug 16, 2016 by meena.p

1 answer

A potential difference applied to an - ray tube is $5kv$ and the current through it is $3.2 \;mA$ Then the number of electrons striking the target per second is

asked Jul 8, 2016 by meena.p

1 answer

An energy of $24.6\;ev$ is required to remove one of the electrons in (ev) is required to remove both the electrons from a neutral helium atom is

asked Jul 8, 2016 by meena.p

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If an $\alpha$ particle collides head on with a nucleus , What is impact parameter?

asked Jul 8, 2016 by meena.p

1 answer

During x- ray formation if voltage is increased,

asked Jul 8, 2016 by meena.p

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What would be the radius of second orbit of $He^{+}$ ion ?

asked Jul 8, 2016 by meena.p

1 answer

The size of the atom is proportional to

asked Jul 8, 2016 by meena.p

1 answer

An electron makes a transition from orbit $n=4$ to the orbit n=2 of a hydrogen atom. What is the wave length of the emitted radiation? (R= Rydberg's constant}

asked Jul 8, 2016 by meena.p

1 answer

An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The coulomb force $\overrightarrow{F}$ between the two is :

asked Jul 8, 2016 by meena.p

1 answer

Hydrogen atoms are excited from ground state to the state of principle quantum number 4, Then the no of spectral lines observed will be

asked Jul 8, 2016 by meena.p

1 answer

Name the spectral series of hydrogen spectrum lying in the infrared region .

asked Jul 8, 2016 by meena.p

1 answer

How much is the radius of Bohr's innermost orbit ?

asked Jul 8, 2016 by meena.p

1 answer

Write an empirical relation for parchen series lies of hydrogen spectrum

asked Jul 8, 2016 by meena.p

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What is the angle of scattering for zero impact parameter ?

asked Jul 8, 2016 by meena.p

1 answer

Name the series of hydrogen spectrum which has least wave length

asked Jul 8, 2016 by meena.p

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The energy of an electron in an excited hydrogen atom is $-3.4 \;ev$ calculate the angular momentum of the electron according to Bohr's theory .

asked Jul 8, 2016 by meena.p

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A photo cell is illuminated by a source of light , which is placed at a distance d. If distance becomes $\large\frac{d}{2}$ then the number of electrons emitted per second will be

asked Jul 5, 2016 by meena.p

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Red light , how ever bright it is , cannot produce the emission of electrons from a clean zinc surface , But even weak ultra violet radiation can do so why ?

asked Jul 5, 2016 by meena.p

1 answer

An electron and a proton each have de-Broglie wave length of $1.00 nm$ . What is the ratio of their linear momenta

asked Jul 5, 2016 by meena.p

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The wave length of $1kev$ photon is $1.24 \times 10^{-9}\;m$. What is the frequency of $1Mev$ photon ?

asked Jul 5, 2016 by meena.p

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Three particles having charges in the ratio of $2:3:5$ produce the same point on the photographic film in Thomson experiment . Their masses are in the ratio of

asked Jul 5, 2016 by meena.p

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The potential difference that much be applied to stop the fastest photo electron emitted by a nickel surface having work function $5.01\;ev$ When ultra violet light 0f 200 nm falls on it , must be

asked Jul 5, 2016 by meena.p

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