Recent questions tagged 2015

The heart of a man pumps 5 liters of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury be $13.6 \times 10^3 \;kg/m^3$ and $g = 10\; m/s^2$, then the power of heart in watt is :

asked Aug 21, 2018 by pady_1

1 answer

Two slits in Youngs experiment have widths in the ratio 1:25. The ratio of intensity at the maxima and minima in the interference pattern, $\frac{I_{max}}{I_{min}}$ is :

asked Aug 21, 2018 by pady_1

1 answer

If potential(in volts) in a region is expressed as $V (x, y, z) = 6xy – y + 2yz$, the electric field (in N/C) at point (1, 1, 0) is :

asked Aug 21, 2018 by pady_1

1 answer

On a frictionless surface, a block of mass $M$ moving at speed v collides elastically with another block of same mass M which is initially at rest. After collision the first block moves at an angle θ to its initial direction and has a speed $\frac{v}{3}$. The second block‘s speed after the collision is :

asked Aug 21, 2018 by pady_1

1 answer

A ball is thrown vertically downwards from a height of $20 m$ with an initial velocity $v_0$. It collides with the ground, loses 50 percent of its energy in collision and rebounds to the same height. The initial velocity $v_0$ is : (Take g = $10 ms^{–2}$)

asked Aug 21, 2018 by pady_1

1 answer

An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas ?

asked Aug 21, 2018 by pady_1

1 answer

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is $–20^°C$, the temperature of the surroundings to which it rejects heat is :

asked Aug 21, 2018 by pady_1

1 answer

Two stones of masses $m$ and $2 m$ are whirled in horizontal circles, the heavier one in a radius $\frac{r}{2}$ and lighter one in radius $r$. The tangential speed of lighter stone is $n$ times that of the value of heavier stone when they experience same centripetal forces. The value of $n$ is :

asked Aug 21, 2018 by pady_1

1 answer

A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30Â°, the box starts to slip and slides 4.0 m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively :

asked Aug 21, 2018 by pady_1

1 answer

A series R-C circuit is connected to an alternating voltage source. Consider two situations: (a) When capacitor is air filled. (b) When capacitor is mica filled. Current through resistor is i and voltage across capacitor is V then :

asked Aug 21, 2018 by pady_1

1 answer

$4.0\; g$ of a gas occupies $22.4 \;liters$ at NTP. The specific heat capacity of the gas at constant volume is $5.0\; JK^{–1} mol^{–1}$. If the speed of sound in this gas at NTP is $952\; ms^{–1}$, then the heat capacity at constant pressure is (Take gas constant $R = 8.3 \;JK^{–1} mol^{–1}$)

asked Aug 21, 2018 by pady_1

1 answer

Light of wavelength 500 nm is incident on a metal with work function 2.28 eV. The de Broglie wavelength of the emitted electron is :

asked Aug 21, 2018 by pady_1

1 answer

Two metal wires of identical dimensions are connected in series. If $\sigma_1$ and $\sigma_2$ are the conductivities of the metal wires respectively, the effective conductivity of the combination is :

asked Aug 21, 2018 by pady_1

1 answer

A nucleus of uranium decays at rest into nuclei of thorium and helium. Then :

asked Aug 21, 2018 by pady_1

1 answer

Two particles A and B, move with constant velocities $\overrightarrow{v_1}$ and $\overrightarrow{v_2}$. At the initial moment their position vectors are $\overrightarrow{r_1}$ and $\overrightarrow{r_2}$ respectively. the condition for particles A and B for their collision is :

asked Aug 21, 2018 by pady_1

1 answer

A force $\overrightarrow{F} = \alpha \hat{i} + 3 \hat {j} + 6 \hat{k}$ is acting at a point $\overrightarrow{r} = 2 \hat{i} -6\hat {j} - 12 \hat{k}$. The value of $\alpha$ for which angular momentum about origin is conserved is :

asked Aug 21, 2018 by pady_1

1 answer

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern, the phase difference between the Huygen’s wavelet from the edge of the slit and the wavelet from the midpoint of the slit is :

asked Aug 21, 2018 by pady_1

1 answer

Point masses $m_1$ and $m_2$ are placed at the opposite ends of a rigid rod of length $L$ and negligible mass. The rod is to be set rotating about an axis perpendicular to it. The position of point $P$ on this rod through which the axis should pass so that the work required to set the rod rotating with angular velocity $\omega_0$ is minimum, is given by :

asked Aug 21, 2018 by pady_1

1 answer

A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. The lowest resonant frequency for this string is :

asked Aug 21, 2018 by pady_1

1 answer

The position vector of a particle $\overrightarrow{R}$ as a function of time is given by : $\overrightarrow{R} = 4 \sin (2 \pi t) \hat{i} + 4 \cos (2 \pi t) \hat{j}$ Where R is in meters, t is in seconds and $\hat{i}$ and $\hat{j}$ denote unit vectors along x- and y-directions, respectively. Which one of the following statements is wrong for the motion of particle ?

asked Aug 21, 2018 by pady_1

1 answer

A remote – sensing satellite of earth revolves in a circular orbit at a height of $0.25 \times 10^6\; m$ above the surface of earth. If earth’s radius is $6.38 \times 10^6\; m$ and $g = 9.8 \;ms^{–2}$, then the orbital speed of the satellite is :

asked Aug 21, 2018 by pady_1

1 answer

In the given figure, a diode D is connected to an external resistance R = 100 $\Omega$ and an e.m.f. of 3.5 V. If the barrier potential developed across the diode is 0.5V, the current in the circuit will be:

asked Aug 21, 2018 by pady_1

1 answer

A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of the earth. Then,

asked Aug 21, 2018 by pady_1

1 answer

Two vessels separately contain two ideal gases A and B at the same temperature, the pressure of A being twice that of B. Under such conditions, the density of A is found to be $1.5$ times the density of B. The ratio of molecular weight of A and B is :

asked Aug 21, 2018 by pady_1

2 answers

A parallel plate air capacitor has capacity $‘C’$, distance of separation between plates is $‘d’$ and potential difference $‘V’$ is applied between the plates. Force of attraction between the plates of the parallel plate air capacitor is :

asked Aug 21, 2018 by pady_1

1 answer

A rectangular coil of length $0.12\; m$ and width $0.1\; m$ having $50$ turns of wire is suspended vertically in a uniform magnetic field of strength $0.2\; Weber/m^2$. The coil carries a current of $2A$. If the plane of the coil is inclined at an angle of $30^°$ with the direction of the field, the torque required to keep the coil in stable equilibrium will be :

asked Aug 21, 2018 by pady_1

1 answer

An automobile moves on a road with a speed of $54\; km\; h^{–1}$. The radius of its wheels is $0.45 \;m$ and the moment of inertia of the wheel about its axis of rotation is $3\; kg \;m^2$. If thevehicle is brought to rest in $15s$, the magnitude of average torque transmitted by its brakes to the wheel is :

asked Aug 21, 2018 by pady_1

1 answer

A source of sound S emitting waves of frequency $100 \;Hz$ and an observer O are located at some distance from each other. The source is moving with a speed of $19.4 ms^{-1}$ at an angle of $60^{A^°}$ with the source observer line as shown in the figure. The observer is at rest. The apparent frequency observed by the observer (velocity of sound in air $330 ms^{-1}$), is :

asked Aug 21, 2018 by pady_1

1 answer

If vectors $\overrightarrow{A} = \cos \omega \hat{i} + \sin \omega \hat{j} $ and $\overrightarrow{B} = \cos \frac{\omega t}{2} \hat{i} + \sin \frac{\omega t}{2} \hat{j} $ are functions of time, then the value of $t$ at which they are orthogonal to each other is :

asked Aug 21, 2018 by pady_1

1 answer

A particle is executing a simple harmonic motion. Its maximum acceleration is $\alpha$ and maximum velocity is $\beta$. Then, its time period of vibration will be:

asked Aug 21, 2018 by pady_1

1 answer

A potentiometer wire of length L and a resistance r are connected in series with a battery of e.m.f. $E_0$ and a resistance $r_1$. An unknown e.m.f. E is balanced at a length l of the potentiometer wire. The e.m.f. E will be given by :

asked Aug 21, 2018 by pady_1

1 answer

The Young’s modulus of steel is twice that of brass. Two wires of same length and of same area of cross section, one of steel and another of brass are suspended from the same roof. If we want the lower ends of the wires to be at the same level, then the weights added to the steel and brass wires must be in the ratio of :

asked Aug 21, 2018 by pady_1

1 answer

The cylindrical tube of a spray pump has radius R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is V, the speed of the ejection of the liquid through the holes is :

asked Aug 21, 2018 by pady_1

1 answer

An electron moves on a straight line path XY as shown. The abcd is a coil adjacent to the path of electron. What will be the direction of current, if any, induced in the coil ?

asked Aug 21, 2018 by pady_1

1 answer

The energy of the em waves is of the order of 15 keV. To which part of the spectrum does it belong ?

asked Aug 21, 2018 by pady_1

1 answer

In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series is :

asked Aug 21, 2018 by pady_1

1 answer

The UN conference of Parties on climate change in the year 2012 was held at :

asked Aug 21, 2018 by pady_1

1 answer

Which of the following pairs is not correctly matched?

asked Aug 21, 2018 by pady_1

1 answer

Which of the following immunoglobulins does constitute the largest percentage in human milk?

asked Aug 21, 2018 by pady_1

1 answer

In photosynthesis, the light-independent reactions take place at :

asked Aug 21, 2018 by pady_1

1 answer

Pick up the wrong statement :

asked Aug 21, 2018 by pady_1

1 answer

The introduction of t-DNA into plants involves -

asked Aug 21, 2018 by pady_1

1 answer

A column of water within xylem vessels of tall trees does not break under its weight because of -

asked Aug 21, 2018 by pady_1

1 answer

Industrial melanism is an example of -

asked Aug 21, 2018 by pady_1

1 answer

Satellite DNA is important because it :

asked Aug 21, 2018 by pady_1

2 answers

Which of the following are most suitable indicators of $SO_2$ pollution in the environment?

asked Aug 21, 2018 by pady_1

1 answer

Name the pulmonary disease in which alveolar surface area involvedin gas exchange is drastically reduced due to damage in the alveolar walls.

asked Aug 21, 2018 by pady_1

1 answer

Balbiani rings are sites of :

asked Aug 21, 2018 by pady_1

1 answer

In the following human pedigree, the filled symbols represent the affected individuals. Identify the type of given pedigree.

asked Aug 21, 2018 by pady_1

1 answer

During ecological succession :

asked Aug 21, 2018 by pady_1

1 answer

Ask Questions, Get Answers