Recent questions tagged 2014

A sinusoidal voltage $\;V(t)=100\;sin (500 t)\;$ is applied across a pure inductance of $\;L=0.02 \;H\;$ . The current through the coil is :

asked May 24, 2014 by yamini.v

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Consider two thin identical conducting wires covered with very thin insulating material . One of the wires is bent into a loop and produces magnetic field $\;B_{1}\;$ , at its center when a current I passes through it .The second wire is bent into a coil with three identical loops adjacent to each other and produces magnetic field $\;B_{2}\;$ at the center of the loops when current $\;\large\frac{I}{3}\;$ passes through it . The ratio $\;B_{1} : B_{2}\;$ is :

asked May 24, 2014 by yamini.v

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A positive charge ' q ' of mass ' m ' is moving along the $\;+ x\;$ axis .We wish to apply a uniform magnetic field B for time $\;\Delta t\;$ so that the charge reverses its direction crossing the y- axis at a distance d . Then :

asked May 24, 2014 by yamini.v

0 answers

The circuit as shown here has two batteries of 8.0 V and 16.0 V and three resistors $\;3 \Omega,9 \Omega\;$ and $\;9 \Omega\;$ and a capacitor $\;5.0\;\mu F\;$ . How much is the current I in the circuit in steady state ?

asked May 24, 2014 by yamini.v

0 answers

The space between the plates of a parallel plate capacitor is filled with a ' dielectric ' whose dielectric constant varies with distance as for the relation : $\;K(x)=K_{0}+\lambda x\;$ ($\lambda\;$)=a constant . The capacitance C , of this capacitor , would be related to its ' vacuum ' capacitance $\;C_{0}\;$ as for the relation :

asked May 24, 2014 by yamini.v

1 answer

A spherically symmetric charge distribution is characterised by a charge density having the following variation : \[\]$\;\rho(r)=\rho_{0}(1-\large\frac{r}{R})\;for\;r < \normalsize R\;$\[\]$\;\rho(r) =0 \;\; r \geq R\;$ \[\] where r is the distance from the center of the charge distribution and $\;\rho_{0}\;$ is a constant .The electric field at an internal point $(r < R)$ is :

asked May 23, 2014 by yamini.v

1 answer

A source of sound A emitting waves of frequency 1800 Hz is falling towards ground with a terminal speed v .The observer B on the ground directly beneath the source receives waves of frequency 2150 Hz .The source A receives waves , reflected from ground , of frequency nearly : (Speed of sound =343 m/s)

asked May 23, 2014 by yamini.v

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Which of the following expressions corresponds to simple harmonic motion along a straight line , where x is the displacement and a,b,c are positive constants ?

asked May 23, 2014 by yamini.v

1 answer

At room temperature a diatomic gas is found to have an r.m.s. speed of $\;1930\;ms^{-1}\;$ .The gas is :

asked May 23, 2014 by yamini.v

1 answer

A car not engine absorbs 1000 J of heat energy from a reservoir at $\;127^{0}C\;$ and rejects 600 J of heat energy during each cycle .The efficiency of engine and temperature of sink will be :

asked May 23, 2014 by yamini.v

0 answers

Hot water cools from $\;60^{0}\;$ to $\;50^{0}\;$ in the first 10 minutes and to $\;42^{0}\;$ in the next 10 minutes .The temperature of the surroundings is :

asked May 23, 2014 by yamini.v

0 answers

Two soap bubbles coalesce to form a single bubble . If V is the subsequent change in volume of contained air and S the change in total surface area , T is the surface tension and P atmospheric pressure ,which of the following relation is correct ?

asked May 23, 2014 by yamini.v

1 answer

A cylindrical vessel of cross - section A contains water to a height h.There is a hole in the bottom of radius ' a ' .The time in which it will be emptied is :

asked May 23, 2014 by yamini.v

0 answers

Steel ruptures when a shear of $\;3.5 \times 10^{8}\;Nm^{-2}\;$ is applied .The force needed to punch a 1 cm diameter hole in a steel sheet 0.3 cm thick is nearly :

asked May 23, 2014 by yamini.v

0 answers

Two hypothetical plates masses $\;m_{1}\;$ and $\;m_{2}\;$ are at rest when they are infinite distance apart .Because of the gravitational force they move towards each other along the line joining their centers .What is their speed when their separation is 'd ' ? (Speed of $\;m_{1}\;$ is $\;v_{1}\;$ and that of $\;m_{2}\;$ is $\;v_{2}\;$)

asked May 23, 2014 by yamini.v

1 answer

A particle is moving in a circular path of radius a , with a constant velocity v as shown in the figure . The center of circle is marked by 'C' .The angular momentum from the origin O can be written as :

asked May 23, 2014 by yamini.v

1 answer

A spring of unstretched length l has a mass m with one end fixed to a rigid support .Assuming spring to be made of a uniform wire , the kinetic energy possessed by it if its free end is pulled with uniform velocity v is :

asked May 23, 2014 by yamini.v

1 answer

A 4 g bullet is fired horizontally with a speed of 300 m/s into 0.8 kg block of wood at rest on a table .If the coefficient of friction between the block and the table is 0.3 , how far will the block side approximately ?

asked May 23, 2014 by yamini.v

1 answer

Three masses m,2m and 3m are moving in x - y plane with speed 3u,2u and u respectively as shown in figure . The three masses collide at the same point at P and stick together .The velocity of resulting mass will be :

asked May 23, 2014 by yamini.v

0 answers

A person climbs up a stalled escalator in 60 s .If standing on the same but escalator running with constant velocity he takes 40 s.How much time is taken by the person to walk up the moving escalator ?

asked May 23, 2014 by yamini.v

0 answers

From the following combinations of physical constants (expressed through their usual symbols) the only combination , that would have the same value in different systems of units , is :

asked May 23, 2014 by yamini.v

1 answer

In the experiment of calibration of voltmeter , a standard cell of e.m.f.1.1 volt is balanced against 440 cm of potentiometer wire .The potential difference across the ends of resistance is found to balance against 220 cm of the wire . The corresponding reading of voltmeter is 0.5 volt .The error in the reading of voltmeter will be :

asked May 23, 2014 by yamini.v

0 answers