Recent questions and answers in 1998-unused

The cause of potential barrier in a P-N junction diode is :

answered Feb 26, 2020 by asksheenh

1 answer

O is the centre of an equilateral triangle ABC $F_1, F_2, F_3$ are three forces acting along the sides AB, BC and AC as shown in fig.What should be the magnitude of $F_3$ so that total torque about O is zero :

answered Sep 13, 2019 by ankit953471

1 answer

Which of the following gives most easily electrophilic substitution reaction :

answered Aug 12, 2019 by sharmaaparna1

1 answer

We consider a thermodynamic system. If $\Delta U$ represents the increase in its internal energy and $W$ the work done by the system, which of the following statement is true?

answered Aug 11, 2019 by parthpatel9974836873

2 answers

If the light of wavelength $\lambda$ is incident on metal surface, the ejected fastest electron has speed v. If the wavelength i changed to $\frac{3 \lambda}{4}$, the speed of the fastest emitted electron will be:

answered Jun 22, 2019 by prajjwal937

1 answer

Two long parallel wires are at a distance of 1m. If both of them carry one ampere of current in same direction, then the force of attraction on unit length of the wire will be :

answered Jan 12, 2019 by ramizuddin1996

1 answer

In the Bohr model of H-atom, an electron (e) is revolving around a proton (p) with velocity v, if r is the radius of orbit and m is mass and $\varepsilon_0$ is vacuum permittivity, the value of v is :

answered Oct 21, 2018 by dksagar19

1 answer

asked Jun 15, 2018 by priyanka.c

0 answers

A cell 'A' with D.P.D. = 8 is surrounded by three cells 'B', 'C' and 'D' with D.P.D. respectively 4, 6 and 5. What shall be the direction of water movement :

asked Jun 15, 2018 by priyanka.c

0 answers

For a Rocket propulsion velocity of exhaust gases relative to rocket is $2\; km/s$. If mass of rocket system is 1000 kg, then the rate of fuel consumption for a rocket to rise up with acceleration $4.9\; m/s^2$ will be :

answered May 8, 2018 by itspriti162

1 answer

Two coil have a mutual inductance 0.005 H. The current changes in first coil according to equation $I = I_0 \sin \omega t $ where $I_0 = 2A$ and $\omega = 100 \pi\; rad/sec$. The maximum value of emf in second coil is

answered Feb 3, 2018 by devan70

1 answer

A gas of volume changes 2 litre to 10 litre at Constant Temperature 300K, then the change in internal energy will be :

answered Jan 12, 2018 by mesamayita

1 answer

If Force $F = 500 - 100 t$, then function of impulse with time will be :

answered Oct 10, 2017 by priyanka.c

1 answer

If $x = 3 - 4t^2 + t^3$, then work done in first $4s$ will be (Mass of the particle is 3 gram) :

answered Oct 10, 2017 by priyanka.c

1 answer

A circular ring of mass M and radius R is rotating about its axis with constant angular velocity $w$. Two particle each of mass $m$ are attached gently to the opposite ends of a diameter of the ting. The angular velocity of the ring will now become :

answered Oct 10, 2017 by priyanka.c

1 answer

Two pendulum suspended from same point having length 2m and 0.5m. If they displaced slightly and released then they will be in same phase, when small pendulum will have completed?

answered Oct 10, 2017 by priyanka.c

1 answer

For a wave $y = y_0 \sin (wt - kx)$, for what value of $\lambda$ is the maximum particle velocity equal to two times the wave velocity :

answered Oct 10, 2017 by priyanka.c

1 answer

Following logic gate is :

answered Oct 10, 2017 by priyanka.c

1 answer

Following table is for which logic gate:

answered Oct 10, 2017 by priyanka.c

1 answer

A hollow sphere of radius 1m is given a positive charge of $10 \mu C$. The electric field at the centre of hollow sphere will be :

answered Oct 10, 2017 by priyanka.c

1 answer

Boron has two isotopes $_5B^{10}$ and $_5B^{11}$. If atomic weight of Boron is 100.81 then ratio of $_5B^{10}$ to $_5B^{11}$ in nature will be :

answered Oct 10, 2017 by priyanka.c

1 answer

A point Q lies on the perpendicular bisector of an electrical dipole of dipole moment p. If the distance of Q from the dipole is r (much larger than the size of the dipole), then the electric field at Q is proportional to :

asked Oct 10, 2017 by priyanka.c

0 answers

A particle, with restoring force proportional to displacement and resisting force proportional to velocity is subjected to a force $F \sin ωt$. If the amplitude of the particle is maximum for $ω = ω_1$ and the energy of the particle maximum for $ω = ω_2$, then :

asked Oct 10, 2017 by priyanka.c

0 answers

Common emitter circuit is used as amplifier, its current gain is 50. If input resistance is $1 K \Omega$ and input voltage is 5 volt then output current will be :

asked Oct 10, 2017 by priyanka.c

0 answers

Radiation energy corresponding to the temperature T of the sun is E. If its temperature is doubled, then its radiation energy will be :

asked Oct 10, 2017 by priyanka.c

0 answers

A rigid rod is placed against the wall as shown in figure. When its velocity of lower end is $10 \;ms^{-1}$ and its base makes an angle $\alpha = 60^{\circ}$ with horizontal, then the vertical velocity of its end B will be :

asked Oct 10, 2017 by priyanka.c

0 answers

For nuclear reaction : <br> $_{92}U^{235} + _0n^1 \to _{56}Ba^{144} + ......... + 3_0n^1$

asked Oct 10, 2017 by priyanka.c

0 answers

If a source moves perpendicularly from listener then the change in frequency will be

asked Oct 10, 2017 by priyanka.c

0 answers

Turn ratio of a step-up transformer is $1 : 25$. If current in load coil is $2A$, then the current in primary coil will be :

asked Oct 10, 2017 by priyanka.c

0 answers

Electric field at the equator of a dipole is E. If strength and distance is now doubled then the electric field will be :

asked Oct 10, 2017 by priyanka.c

0 answers

A charge q is placed in an uniform electric field E. If it is released, then the K.E of the charge after travelling distance y will be :

asked Oct 10, 2017 by priyanka.c

0 answers

A car is moving with velocity V. If stop after applying break at a distance of 20 m. If velocity of car is doubled, then how much distance it will cover (travel) after applying break :

asked Oct 10, 2017 by priyanka.c

0 answers

Is $R_s$ is the equivalent resistance of n resistances in series and $R_p$ is the equivalent resistance of n resistances in parallel then $\frac{R_s}{R_p}$ is

asked Oct 10, 2017 by priyanka.c

0 answers