Recent questions tagged 41

Among the following, the reaction that proceeds through an electrophilic substitution is :

asked Jul 8, 2019 by pady_1

1 answer

A current carrying wire produces in the neighbourhood :

asked Dec 19, 2018 by pady_1

1 answer

A parallel plate capacitor filled with a dielectric of relative permitivity 5 between its plates is charged to acquire an energy $E$ and isolated. If the dielectric is replaced by another of relative permitivity 2, its energy becomes:

asked Dec 19, 2018 by pady_1

0 answers

A vessel is filled with an ideal gas at a pressure of $10$ atmosphere and temperature $27^{\circ}C$. Half of the mass of the gas is removed from the vessel and temperature of the remaining gas is increased to $87^{\circ}C$. Then the pressure of the gas in the vessel will be :

asked Dec 19, 2018 by pady_1

0 answers

A uniform metal rod of length 'L' and mass 'M' is rotating about an axis passing through one of the ends & perpendicular to the rod with angular speed $'\omega'$. If the temperature increases by $t^{\circ}C$, then the change in its angular velocity is proportional to which of the following ? (Coefficient of linear expansion of rod = $\alpha$)

asked Dec 11, 2018 by pady_1

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Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will :

asked Dec 11, 2018 by pady_1

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In an oscillating LC circuit the maximum charge on the capacitaor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is :

asked Dec 11, 2018 by pady_1

0 answers

Two sets A and B are as under : $A =\{ (a,b) \in R \times R : |a-5|<1$ and $|b-5| <1\} $; $B= \{(a,b) \in R \times R$: $4(a-6)^2 + 9(b-5)^2 \leq 36 \}$. Then ;

asked Dec 11, 2018 by pady_1

1 answer

A particle A of mass m and initial velocity $v$ collides with a particle B of mass $\frac{m}{2}$ which is at rest. The collision is head on, and elastic. The ratio of the de-Broglie wavelengths $\lambda_A$ to $\lambda_B$ after the collision is :

asked Dec 11, 2018 by pady_1

0 answers

Which of the following atoms has the highest first ionization energy ?

asked Dec 11, 2018 by pady_1

0 answers

In the long form of the periodic table, the valence shell electronic configuration of $5s^2 5p^4$ corresponds to the element present in :

asked Dec 11, 2018 by pady_1

0 answers

If z is a complex number such that $|z| \geq 2$, then the minimum value of $| x + \frac{1}{2} |$

asked Dec 11, 2018 by pady_1

1 answer

The sum of first 20 terms of the sequence 0.7, 0.77, 0.777, ….. , is

asked Dec 11, 2018 by pady_1

1 answer

A liquid in a beaker has temperature $\theta(t)$ at time $t$ and $\theta_0$ is temperature of surroundings, then according to Newton's law of cooling the correct graph between $log_e (\theta - \theta_0)$ and $t$ is

asked Dec 11, 2018 by pady_1

0 answers

Consider 5 independent Bernoulli's trials each with probability of success p. If the probability of at least one failure is greater than or equal to $\frac{31}{32}$, then p lies in the interval

asked Dec 11, 2018 by pady_1

0 answers

The speed of daughter nuclei is

asked Dec 11, 2018 by pady_1

0 answers

Two liquid X and Y form an ideal solution. At 300 K, vapour pressure of the solution containing 1 mol of X and 3 mol of Y is 550 mm Hg. At the same temperature, if 1 mol of Y is further added to this solution, vapour pressure of the solution increases by 10 mm Hg. Vapour pressure (in mm Hg) of X and Y in their pure states will be, respectively :

asked Nov 29, 2018 by pady_1

0 answers

In the following sequence of reactions, the alkene affords the compound ‘B’ $CH_3CH = CHCH_3 \xrightarrow{O_3} A \xrightarrow[\text{Zn}]{\text{$H_2O$}} B$ The compound is :

asked Nov 29, 2018 by pady_1

0 answers

The displacement of an object attached to a spring and executing simple harmonic motion is given by $x = 2 \times 10^{-2} \cos \pi t \; metre$. The time at which the maximum speed first occurs is :

asked Nov 29, 2018 by pady_1

0 answers

An electric bulb is rated 220 volt - 100 watt. The power consumed by it when operated on 110 volt will be :

asked Nov 13, 2018 by pady_1

0 answers

If $\begin {align}I_1 = \int_0^1 2^{x^2} \; \; dx , I_2 = \int_0^1 2 ^{x^3} \;\; dx, I_3 = \int_1^2 2^{x^2} \; \; dx \; and \; I_4 = \int_1^2 2^{x^3} \;\; dx, \end{align}$ then :

asked Nov 5, 2018 by pady_1

0 answers

A thin glass (refractive index 1.5) lens has optical power of -5 D in air. Its optical power in a liquid medium with refractive index 1.6 will be :

asked Nov 5, 2018 by pady_1

0 answers

If $ \begin{align} f(x) = \frac{e^x}{1+e^x}, \; I_1 = \int_{f(-a)}^{f(a)} xg \{ x (1-x) \} dx \end{align} $ and $\begin{align}I_2 = \int_{f(-a)}^{f(a)} g \{x(1-x)\} \end{align}$ then the value of $\frac{I_2}{I_1}$ is

asked Nov 5, 2018 by pady_1

0 answers

A small sphere of radius 'r' falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to

asked Aug 21, 2018 by pady_1

1 answer

The element Z = 114 has been discovered recently. It will belong to which of the following family/group and electronic configuration ?

asked Aug 21, 2018 by pady_1

2 answers

Consider the following liquid-vapour equilibrium $Liquid \rightleftharpoons Vapour$ Which of the following relations is correct ?

asked Aug 21, 2018 by pady_1

1 answer

asked Aug 21, 2018 by pady_1

1 answer

Hydrogen atom in ground state is excited by a monochromatic radiation of $\lambda= 975 A^o$. Number of spectral lines in the resulting spectrum emitted will be :

asked Aug 20, 2018 by pady_1

1 answer

In Young’s double slit experiment, the slits are 2mm apart and are illuminated by photons of two wavelengths $\lambda_1 = 12000 Å$ and $\lambda_2 = 10000 Å$. At what minimum distance from the common central bright fringe on the screen 2m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other ?

asked Aug 20, 2018 by pady_1

1 answer

A 200 W sodium street lamp emits yellow light of wavelength $0.6 \mu m$. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is .

asked Aug 20, 2018 by pady_1

1 answer

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speeds of emitted electrons will be :

asked Aug 16, 2018 by pady_1

1 answer

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

asked Jul 26, 2018 by pady_1

1 answer

The figure shows a plot of photo current versus anode potential for a photo sensitive surface for three different radiations. Which one of the following is a correct statement ?

asked Jul 26, 2018 by pady_1

2 answers

A current of 3 amp. flows through the $2\Omega$ resistor shown in the circuit. The power dissipated in the $5\Omega$ resistor is -

asked Jul 26, 2018 by pady_1

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 :-

asked Jul 26, 2018 by pady_1

1 answer

Above Curie temperature:-

asked Jul 25, 2018 by pady_1

1 answer

Imagine a new planet having the same density as that of earth but it is 3 times bigger than the earth in size. If the acceleration due to gravity on the surface of earth is g and that on the surface of the new planet is g', then -

asked Jul 24, 2018 by pady_1

1 answer

In a p–n junction photo cell, the value of the photo electromotive force produced by monochromatic light is proportional to: -

asked Jul 24, 2018 by pady_1

1 answer

Which of the following ray are not electromagnetic waves

asked Jul 24, 2018 by pady_1

1 answer

To convert a galvanometer into a voltmeter one should connect a : -

asked Jul 23, 2018 by pady_1

2 answers

The energy of hydrogen atom in $n^{th}$ orbit is $E_n$ then the energy in nth orbit of singly ionised helium atom will be : -

asked Jul 20, 2018 by pady_1

1 answer

According to the Faraday Law of electrolysis, the mass deposited at electrode proportional to :

asked Jul 20, 2018 by pady_1

1 answer

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 Jun 15, 2018 by pady_1

1 answer

The purple ribbon is shorter than the yellow ribbon. The purple ribbon is longer than the white ribbon. Which ribbon is the shortest?

asked Dec 31, 2015 by pady_1

1 answer

The number of lines of a symmetry in a divider is

asked Dec 31, 2015 by pady_1

1 answer

Express 93 l in dl

asked Dec 31, 2015 by pady_1

1 answer

Vinayak ate $\large\frac{1}{6}$ of a pizza and his friend Bala ate $\large\frac{8}{15}$ of the pizza. How much total pizza did they eat altogether?

asked Dec 31, 2015 by pady_1

0 answers

The month before the chicken farm expanded, it produced 9,228 eggs. The month after, it produced 6,870 more eggs than that. How many eggs were produced that month?

asked Dec 31, 2015 by pady_1

0 answers

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