Recent questions and answers in 2007

Which one of the following statements is correct ?

answered Jul 17, 2020 by kphasnashirin

1 answer

For a cubic crystal structure which one of the following relations indicting the cell characteristic is correct :-

answered Apr 21, 2020 by meena.clay6

2 answers

In the following circuit, the output Y for all possible inputs A and B is expresed by the truth table :-

answered Apr 21, 2020 by meena.clay6

1 answer

A common emitter amplifier has voltage gain of 50, an input impedance of 100 $\Omega$ and an output impedance of 200 $\Omega$. The power gain of the amplifier is :-

answered Apr 21, 2020 by meena.clay6

1 answer

In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is :- <img src""/>

answered Apr 21, 2020 by meena.clay6

1 answer

The total energy of electron in the ground state of hydrogen atom is -13.6 eV. The kinetic energy of an electron in first excited state is :-

answered Apr 21, 2020 by meena.clay6

2 answers

Two radioactive substances A and B have decay constants $5 \lambda$ and $\lambda $ respectively. At $t=0$ they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be $(\frac{1}{e} )^2$ after a time interval :-

answered Apr 21, 2020 by meena.clay6

1 answer

A nucleus $^A_Z X$ has mass represented by $M(A,Z)$. If $M_p$ and $M_n$ denote the mass of proton and neutron respectively and B.E. the binding energy in MeV, then:

answered Apr 21, 2020 by meena.clay6

1 answer

In radioactive decay process, the negatively charged emitted $\beta$- particles are :-

answered Apr 21, 2020 by meena.clay6

1 answer

If the nucleus $^{27}_{13}Al$ has a nuclear radius of about 3.6 fm, the $^{125}_{52}Te$ would have its radius approximately as :-

answered Apr 21, 2020 by meena.clay6

1 answer

In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential V and then made to describe semicircular paths of radius R using a magnetic field B. If V and B are kept constant, the ratio $\frac{Charge\; on\; the ion}{mass\; of\; the\; ion}$ will be proportional to :-

answered Apr 21, 2020 by meena.clay6

1 answer

Monochromatic light of frequency $6.0 \times 10^{14}$ Hz is produced by a laser. The power emitted is $2 \times 10^{-3}$W. The number of photons emitted, on the average, by the source per second is :-

answered Apr 21, 2020 by meena.clay6

1 answer

A 5 watt source emits monochromatic light of wavelength 5000 Å. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.0m, the number of photo electrons liberated will :

answered Apr 21, 2020 by meena.clay6

1 answer

Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature then it will show :-

answered Apr 21, 2020 by meena.clay6

1 answer

A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 amp, the efficiency of the transformer is approximately-

answered Apr 21, 2020 by meena.clay6

1 answer

What is the value of inductance L for which the current is a maximum in a series LCR circuit with $C = 10 \mu F$ and $\omega = 1000^{-1}$

answered Apr 21, 2020 by meena.clay6

1 answer

The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux $\phi$ linked with the primary coil is given by $\phi = \phi_0 + 4t$, where $\phi$ is in webers, t is time in seconds and $\phi_0$ is a constant, the output voltage across the secondary coil is :

answered Apr 21, 2020 by meena.clay6

1 answer

A beam of electrons passes undeflected through mutually perpendicular electric and magnetic fields. It the electric field is switched off, and the same magnetic field is maintained, the electrons move :

answered Apr 21, 2020 by meena.clay6

1 answer

A charged particle (charge q) is moving in a circle of radius R with uniform speed v. The associated magnetic moment $\mu$ is given by:

answered Apr 21, 2020 by meena.clay6

1 answer

Under the influence of a uniform magnetic field a charged particle is moving in a circle of radius R with constant speed v. The time period of the motion-

answered Apr 20, 2020 by meena.clay6

1 answer

The resistance of an ammeter is $13 \Omega $ and its scale is graduated for a current upto $100$ amps. After and additional shunt has been connected to this ammeter it becomes possible to measure currents upto $750$ amperes by this meter. The value of shunt-resistance is-

answered Apr 20, 2020 by meena.clay6

1 answer

Three resistances P, Q, R each of $2 \Omega$ and an unknown resistance S form the four arms of a Wheatstone bridge circuit. When a resistance of $6 \Omega$ is connected in parallel to S the bridge gets balanced. What is the value of S ?

answered Apr 20, 2020 by meena.clay6

1 answer

If the cold junction of a thermo-couple is kept at $0^{\circ}C$ and the hot junction is kept at $T^{\circ}C$, then the relation between neutral temperature $(T_n)$ and temperature of inversion $(T_i)$ is:

answered Apr 20, 2020 by meena.clay6

1 answer

A steady current of $1.5$ amp flows through a copper voltameter for 10 minutes. If the electrochemical equivalent of copper is $30 \times 10^{–5}$ gm $coulomb^{–1}$, the mass of copper deposited on the electrode will be: -

answered Apr 16, 2020 by meena.clay6

1 answer

The total power dissipated in watts in the circuit shown here is :-

answered Apr 14, 2020 by meena.clay6

1 answer

Two condensers, one of capacity $C$ and the other of capacity $\frac{C}{2}$ , are connected to a V-volt battery, as shown- The work done in charging fully both the condensers is :

answered Apr 14, 2020 by meena.clay6

1 answer

Three point charges +q, –2q and +q are placed at points (x = 0, y = a, z = 0), (x = 0,y = 0, z = 0) and (x = a, y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are:-

answered Apr 14, 2020 by meena.clay6

1 answer

A hollow cylinder has a charge q coulomb within it. If $\phi$ is the electric flux in units of voltmeter associated with the curved surface B, the flux linked with the plane surface A in units of voltmeter will be- <img src =""/>

answered Apr 14, 2020 by meena.clay6

1 answer

Charge +q and â€“q are placed at points A and B respectively which are at distance $2L$ apart, C is the midpoint between A and B. The work done in moving a charge + Q along the semicircle CRD is:-

answered Apr 14, 2020 by meena.clay6

1 answer

A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure) How fast is the light traveling in the liquid ?

answered Apr 14, 2020 by meena.clay6

1 answer

The electric and magnetic field of an electromagnetic wave are:-

answered Apr 14, 2020 by meena.clay6

1 answer

A particle executes simple harmonic oscillation with an amplitude a. The period of oscillation is T. The minimum time taken by the particle to travel half of the amplitude from the equilibrium position is:

answered Apr 14, 2020 by meena.clay6

1 answer

The particle executing simple harmonic motion has a ienetic energy $K_0 \cos^2 ωt$. The maximum values of the potential energy and the total energy are respectively:-

answered Apr 14, 2020 by meena.clay6

1 answer

The phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is :-

answered Apr 14, 2020 by meena.clay6

1 answer

The frequency of a light wave in a material is $2 \times 10^{14}$ Hz and wavelength is $5000$ Å. The refractive index of material will be:-

answered Apr 14, 2020 by meena.clay6

1 answer

A black body is at $727^{\circ}C$. It emits energy at a rate which is proportional to:

answered Apr 14, 2020 by meena.clay6

1 answer

Lysozyme that is present in perspiration, saliva and tears, destroys:

answered Feb 4, 2020 by meena.clay6

1 answer

Ultrasound of how much frequency is beamed into human body for sonography ?

answered Feb 4, 2020 by meena.clay6

2 answers

Which one of the following is a viral disease of poultry ?

answered Feb 4, 2020 by meena.clay6

2 answers

Which one of the following pairs is mismatched ?

answered Feb 4, 2020 by meena.clay6

1 answer

Which one of the following pairs is wrongly matched ?

answered Feb 4, 2020 by meena.clay6

1 answer

A human male produces sperms with the genotypes AB, Ab, AB, and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person ?

answered Feb 4, 2020 by meena.clay6

1 answer

Increased asthmatic attacks in certain seasons are related to:

answered Feb 4, 2020 by meena.clay6

1 answer

Bowman's glands are located in the

answered Feb 4, 2020 by meena.clay6

2 answers

Probiotics are-

answered Feb 4, 2020 by meena.clay6

2 answers

A plant requires magnesium for:

answered Feb 4, 2020 by meena.clay6

2 answers

The two polynucleotide chain in DNA are:-

answered Feb 4, 2020 by meena.clay6

1 answer

The population of an insect species shows an explosive increase in numbers during rainy season followed by its disappearance at the end of the season. What does this show ?

answered Feb 3, 2020 by meena.clay6

1 answer

In cloning of cattle a fertilized egg is taken out of the mother's womb and:-

answered Feb 3, 2020 by meena.clay6

1 answer

The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated ?

answered Feb 3, 2020 by meena.clay6

1 answer

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