Recent questions tagged 46

In which of the following processes, heat is neither absorbed nor released by a system ?

asked Jul 8, 2019 by pady_1

1 answer

The number of $\alpha$ and $\beta$ particles, respectively, emitted in the radioactive decay $ _{90}X^{200} \to _{80}Y^{168}$ are :

asked Dec 19, 2018 by pady_1

0 answers

In hydrogen spectrum the shortest wavelength in Balmer series is $\lambda$. The shortest wave length in Bracket series will be :

asked Dec 19, 2018 by pady_1

0 answers

Two metal rods A and B of equal lengths and equal cross-sectional areas are joined end to end. The coefficients of thermal conductivities of A and B are in the ratio 2:3, when the free end of A is maintained at $100^{\circ}C$ and the free end of B is maintained at $0^{\circ}C$, the temperature of the junction is :

asked Dec 19, 2018 by pady_1

1 answer

The length of an elastic string is $'a'$ metres when the longitudinal tension is 4 N and $'b'$ meters when the longitudinal tension is 5 N. The length of the string in metres when the longitudinal tension is 9 N is :

asked Dec 11, 2018 by pady_1

0 answers

In a simple harmonic oscillator, at the mean position :

asked Dec 11, 2018 by pady_1

0 answers

Two identical, photocathodes recieve light of frequencies $f_1$ and $f_2$. If the velocities of the photoelectrons (of mass m) coming out are respecitvely $\nu_1$ and $\nu_2$, then :

asked Dec 11, 2018 by pady_1

0 answers

Let $a_1, a_2, a_3,.....,a_{49}$ be in A.P. such that $\displaystyle\sum_{k=0}^{12} a_{4k+1}=416$ and $a_9 + a_{43} =66$. If $a_1^2 + a_2^2....a_{17}^2=140\;m$ then $m$ is equal to :

asked Dec 11, 2018 by pady_1

1 answer

Some energy levels of a molecule are shown in the figure. The ratio of the wavelengths $r = \lambda_1/\lambda_2$, is given by :

asked Dec 11, 2018 by pady_1

0 answers

The pair in which phosphorous atoms have a formal oxidation state of +3 is :

asked Dec 11, 2018 by pady_1

0 answers

The geometry of $XeOF_4$ by VSEPR theory is :

asked Dec 11, 2018 by pady_1

0 answers

et A and B be two events such that $P (\overline{A \cup B}) = \frac{1}{6} , \; P ( A \cap B) = \frac{1}{4} $ and $P(\overline{A}) = \frac{1}{4}$ , where $\overline{A}$ stands for the complement of the event A. Then the events A and B are

asked Dec 11, 2018 by pady_1

1 answer

$\displaystyle{\lim_{x \to 0} \frac{(1 - \cos 2x) ( 3 + \cos x)}{ x \tan 4 x}}$ is equal to

asked Dec 11, 2018 by pady_1

1 answer

This question has statement 1 and statement 2. Of the four choices given after the statements, choose the one that best describes the two statements Statement 1 : Davisson-germer experiment established the wave nature of electrons. Statement 2 : If electrons have wave nature, they can interfere and show diffraction.

asked Dec 11, 2018 by pady_1

0 answers

Equation of the ellipse whose axes are the axes of coordinates and which passes through the point (-3, 1) and has eccentricity $\sqrt{\frac{2}{5}}$ is

asked Dec 11, 2018 by pady_1

0 answers

If a source of power 4 kW produces $10^{20}$ photons/second, the radiation belong to a part of the spectrum called

asked Dec 11, 2018 by pady_1

0 answers

Which of the following has as optical isomer ?

asked Nov 29, 2018 by pady_1

0 answers

The equilibrium constants $K_{p_{1}}$ and $K_{p_{2}}$ for the reactions X = 2Y and Z = P + Q, respectively are in the ratio of 1 : 9. If the degree of dissociation of X and Z be equal then the ratio of total pressure at these equilibria is

asked Nov 29, 2018 by pady_1

0 answers

A long straight wire of radius $a$ carries a steady current $i$. The current is uniformly distributed across its cross-section. The ratio of the magnetic field at $\frac{a}{2}$ and $2a$ is :

asked Nov 29, 2018 by pady_1

0 answers

The potential energy of a 1 kg particle free to move along the $x$-axis is given by $V(x) = (\frac{x^4}{4} - \frac{x^2}{2} ) J$ The total mechanical energy of the particle is $2J$. Then, the maximum speed (in m/s) is:

asked Nov 13, 2018 by pady_1

0 answers

For any vector $\overrightarrow{a}$, the value of $(\overrightarrow{a} \times \hat{i})^2+ (\overrightarrow{a} \times \hat{j})^2 + ( \overrightarrow{a} \times \hat{k})^2$ is equal to :

asked Nov 5, 2018 by pady_1

0 answers

A nuclear transformation is denoted by $X(n, \alpha) \to ^7_3 Li$. Which of the following is the nucleus of element $X$ ?

asked Nov 5, 2018 by pady_1

0 answers

The equation of the straight line passing through the point $(4, 3)$ and making intercepts on the co-ordinate axes whose sum is $-1$ is

asked Nov 5, 2018 by pady_1

0 answers

Which of the following oxides is most acidic in nature ?

asked Aug 21, 2018 by pady_1

1 answer

Asymptote in a logistic growth curve is obtained when :

asked Aug 21, 2018 by pady_1

1 answer

The two polypeptides of human insulin are linked together by

asked Aug 21, 2018 by pady_1

2 answers

Root pressure develops due to -

asked Aug 21, 2018 by pady_1

1 answer

What is the maximum number of orbitals that can be identified with the following quantum number n = 3, $\ell$ = 1, m = 0

asked Aug 20, 2018 by pady_1

1 answer

The value of Planck's constant is $6.63 \times 10^{-34} Js$. The speed of light is $3 \times 10^{17} nms^{-1}$. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of $6 \times 10^{15} s^{-1}$ ?

asked Aug 20, 2018 by pady_1

1 answer

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is

asked Aug 20, 2018 by pady_1

1 answer

A nucleus $_n^m{X}$ emits one α particle and two β– particles. The resulting nucleus is :

asked Aug 16, 2018 by pady_1

1 answer

A series combination of $n_1$ capacitors, each of value $C_1$ , is charged by a source of potential difference 4V. When another parallel combination of $n_2$ capacitors, each of value $C_2$, is charged by a source of potential difference V, it is has the same (total) energy stored in it, as the first combination has. The value of $C_2$, in terms of $C_1$, is then –

asked Jul 26, 2018 by pady_1

1 answer

The mean free path of electrons in a metal is $4\times10^-8$ m. The electric field which can give on an average 2 eV energy to an electron in the metal will be in units of V/m :

asked Jul 26, 2018 by pady_1

1 answer

At 10ºC the value of the density of a fixed mass of an ideal gas divided by its pressure is x. At 110ºC this ratio is -

asked Jul 26, 2018 by pady_1

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 :-

asked Jul 26, 2018 by pady_1

2 answers

A square surface of side L metres is in the plane of the paper. A uniform electric field E(volt/m), also in the plane of the paper, is limited only to the lower half of the square surface, (see figure). The electric flux in SI units associated with the surface is:- r E

asked Jul 25, 2018 by pady_1

2 answers

Energy levels A, B and C of a certain atom correspond to increasing values of energy i.e. ${E_A}<{E_B}<{E_C}$ . If${\lambda_1},{\lambda_2},{\lambda_3}$ are wave lengths of radiations corresponding to transitions C to B, B to A and C to A respectively, which of the following relations is correct -

asked Jul 24, 2018 by pady_1

1 answer

One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at consta pressure and at constant volume is $\frac {5} {3}$, the final temperature of gas will be :-

asked Jul 24, 2018 by pady_1

2 answers

Barrier potential of a p-n junction diode does not depend on -

asked Jul 24, 2018 by pady_1

1 answer

A charge 'q' moves in a region where electric field and magnetic field both exist, then force on it is : -

asked Jul 23, 2018 by pady_1

0 answers

250 N force is required to raise 75 kg mass from a pulley. If rope is pulled 12 m then the load is lifted to 3m, the efficiency of pulley system will be : -

asked Jul 20, 2018 by pady_1

2 answers

The life span of atomic hydrogen is :

asked Jul 20, 2018 by pady_1

2 answers

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

asked Jun 15, 2018 by pady_1

1 answer

A housekeeper leaves home to visit his customers. He drives 4 kilometres east, 1 kilometre south, 7 kilometres west, 5 kilometres north, and 4 kilometres south. How far and in which direction must the housekeeper go to get back to his home?

asked Dec 31, 2015 by pady_1

1 answer

Of the students in Josh's class, 4 have been to Montana and 6 have been to Washington. 3 students have been to both Montana and Washington. How many students have been to Montana or Washington or both?

asked Dec 31, 2015 by pady_1

0 answers

A square lounge has sides that are 9 metres long. What is the lounge's perimeter?

asked Dec 31, 2015 by pady_1

0 answers

Balvinder is reading a mystery novel and this book has 460 pages. Balvinder manages to read $\large\frac{9}{46}$ of the book every day. After 4 days, how many pages does he have left to read?

asked Dec 31, 2015 by pady_1

1 answer

The denominator of a fraction is 3 more than the numerator. If both the numerator and the denominator are increased by 4, the fraction becomes $\large\frac{4}{5}$ What was the original fraction?

asked Dec 31, 2015 by pady_1

0 answers

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