Recent questions tagged 20

The structure of intermediate A in the following reaction is :-

asked Jul 10, 2019 by pady_1

1 answer

A glass flask of volume $200 \; cm^3$ is completely filled with mercury at $20^{\circ}C$. The amount of mercury that spilt over when the flask is heated to $80^{\circ}C$ is (coefficient of volume expansion for glass $27 \times 10^{-8} /^{\circ}C$, mercury $0.18 \times 10^{-8}/^{\circ}C$) :

asked Dec 19, 2018 by pady_1

0 answers

Two simple pendulums of lengths $16 l$ and $l$ are in phase at the mean position at a certain time. If $T$ is the time period of shorter pendulum, the minimum time after which they will be again in phase :

asked Dec 19, 2018 by pady_1

1 answer

Consider the following statements A and B and identify the correct choice of the given answers : (A) The width of the depletion layer in a $p-n$ junction diode increases in forward bias. (B) In a intrinsic semiconductor the fermi energy level in exactly in the middle of the forbidden energy gap.

asked Dec 19, 2018 by pady_1

0 answers

A closed hollow insulated cylinder is filled with gas at $0^{\circ}C$ and also contain an insulated piston of negligible weight and negligible thickness at the middle point. The gas in one side of the piston is heated to $100^{\circ}C$. If the piston moves $5\; cm$. The length of the hollow cylinder is :

asked Dec 11, 2018 by pady_1

0 answers

Wavelength of light used in optical instrument are $\lambda_1 = 4000 \mathring{A}$ and $\lambda_2 = 5000 \mathring{A}$, then ratio of their respective resolving powers (corresponding to $\lambda_1$ and $\lambda_2$) is :

asked Dec 11, 2018 by pady_1

0 answers

The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the :

asked Dec 11, 2018 by pady_1

0 answers

The angular width of the central maximum in a single slit diffraction pattern is $60^{\circ}$. The width of the slit is $ 1\; \mu m$. The slit is illuminated by monochromatic plane waves. If another slit of same width is made near it, Young's fringes can be observed on a screen placed at a distance 50 cm from the slits. If the observed fringe width is 1 cm, what is slit separation distance? (i.e. distance between the centres of each slit.)

asked Dec 11, 2018 by pady_1

0 answers

$\displaystyle\lim_{x \to \frac{\pi}{2}} \frac{\cot x - \cos x}{(\pi - 2 x)^3}$ equals

asked Dec 11, 2018 by pady_1

1 answer

The box of a pin hole camera, of length L, has a hole of radius $a$. It is assumed that when the hole is illuminated by a parallel beam of light of wavelength $\lambda$ the spread of the spot (obtained on the opposite wall of the camera) is the sum of its geometrical spread and the spread due to diffraction. The spot would then have its minimum size (say $b_{min}$) when :

asked Dec 11, 2018 by pady_1

0 answers

A $25 \;cm$ long solenoid has radius $2\; cm$ and $500$ total number of turns. It carries a current of $15\; A$. If it is equivalent to a magnet of the same size and magnetization $\overrightarrow{M}$ (magnetic moment/volume), then $|\overrightarrow{M}|$ is :

asked Dec 11, 2018 by pady_1

0 answers

Three rods of Copper, Brass and Steel are welded together to from a Y –shaped structure. Area of cross – section of each rod = $4\; cm^2$ . End of copper rod is maintained at $100^{\circ}C$ where as ends of brass and steel are kept at $0^{\circ}C$. Lengths of the copper, brass and steel rods are 46, 13 and 12 cms respectively. The rods are thermally insulated from surroundings except at ends. Thermal conductivities of copper, brass and steel are 0.92, 0.26 and 0.12 CGS units respectively. Rate of heat flow through copper rod is :

asked Dec 11, 2018 by pady_1

0 answers

A gaseous hydrocarbon given upon combustion 0.72 g of water and 3.08 g of $CO_2$. The empirical formula of the hydrocarbon is :

asked Dec 11, 2018 by pady_1

0 answers

If the lines $\frac{x-1}{2} = \frac{y+1}{3} = \frac{z-1}{4}$ and $ \frac{x-3}{1} = \frac{y-k}{2} = \frac{z}{1}$ intersect, then $k$ is equal to

asked Dec 11, 2018 by pady_1

1 answer

A resistor 'R' and $2 \mu F$ capacitor in series is connected through a switch to 200 V direct supply. Across the capacitor is a neon bulb that lights up at 120 V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed. ($\log_{10} 2.5 = 0.4$)

asked Dec 11, 2018 by pady_1

0 answers

The correct order of increasing basicity of the given conjugate bases $(R = CH_3)$ is

asked Dec 11, 2018 by pady_1

0 answers

A charge Q is placed at each of the opposite corners of a square. A charge q is placed at each of the other two corners. If the net electrical force on Q is zero, tthen the Q/q equals

asked Nov 29, 2018 by pady_1

0 answers

Let p be the statement “x is an irrational number”, q be the statement “y is a transcendental number”, and r be the statement “x is a rational number iff y is a transcendental number”. Statement –1: r is equivalent to either q or p Statement –2: r is equivalent to $\sim (p\leftrightarrow \sim q)$.

asked Nov 29, 2018 by pady_1

0 answers

If a line makes an angle of $\frac{\pi}{4}$ with the positive directions of each of $x-axis$ and $y-axis$, then the angle that the line makes with the positive direction of the $z-axis$ is :

asked Nov 29, 2018 by pady_1

0 answers

A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple i kept hot and the other is kept cold, then, an electrix current will :

asked Nov 13, 2018 by pady_1

0 answers

If $a^2+b^2+c^2 = -2$ and $f(x) = \begin{vmatrix} 1+a^2x & (1+b^2)x & (1+c^2) x \\ (1+a^2)x & 1+b^2x & (1+c^2)x \\ (1+a^2)x & (1+b^2)x & 1+c^2x \end{vmatrix}$, then $f(x)$ is a polynomial of degree :

asked Nov 5, 2018 by pady_1

0 answers

Average density of the earth :

asked Nov 5, 2018 by pady_1

0 answers

The sum of series $\frac{1}{2!} + \frac{1}{4!} + \frac{1}{6!}+... $ is

asked Nov 5, 2018 by pady_1

0 answers

In Young's double slit experiment the separation d between the slit is 2mm, the wavelength $\lambda$ of the light used is $5896 \; A^o$ and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is $0.20^o$. To increase the fringe angular width to $0.21^o$ ( with same $\lambda$ and D ) the separation between the slits needs to be changed to

asked Aug 21, 2018 by pady_1

1 answer

A 20 litre container at 400 K contains $CO_2(g)$ at pressure $0.4\; atm$ and an excess of $SrO$ (neglect the volume of solid $SrO$). The volume of the container is now decreased by moving the movable piston fitted in the container. The maximum volume of the container, when pressure of $CO_2$ attains its maximum value, will be : (Given that : $SrCO_3 (s) \stackrel{K}\rightleftharpoons SrO (s) + CO_2 (g), Kp = 1.6 \; atm$ )

asked Aug 21, 2018 by pady_1

1 answer

Which one of the following statements is correct when $SO_2$ is passed through acidified $K_2Cr_2O_7$ solution ?

asked Aug 21, 2018 by pady_1

1 answer

If Avogadro number NA, is changed from $6.022 \times 10^{23} mol^{–1}$ to $6.022 \times 10^{20} \;mol^{–1}$, this would change :

asked Aug 21, 2018 by pady_1

1 answer

If $n_1$, $n_2$ and $n_3$ are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by:

asked Aug 20, 2018 by pady_1

1 answer

A wave travelling in the +ve x-direction having displacement along y-direction as 1m, wavelength $2 \pi m$ and frequency of $\frac{1}{\pi}$ Hz is represented by :

asked Aug 20, 2018 by pady_1

1 answer

If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q ?

asked Aug 20, 2018 by pady_1

1 answer

The rate of increase of thermo - e.m.f. with temperature at the neutral temperature of a thermocouple :

asked Aug 16, 2018 by pady_1

1 answer

The activity of a radioactive sample is measured as N0 counts per minute at t = 0 and N0/e counts per minute at t = 5 minutes. The time (in minutes) at which the activity reduces to half its value is –

asked Jul 26, 2018 by pady_1

2 answers

A simple pendulum performs simple harmonic motion about x = 0 with an amplitude a and time period T. The speed of the pendulum at $x=a/2$will be :

asked Jul 26, 2018 by pady_1

1 answer

In the circuit shown, the current through the 4$\Omega$ resistor is 1 amp when the points P and M are connected to a D.C. voltage source. The potential difference between the points M and N is

asked Jul 26, 2018 by pady_1

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:

asked Jul 26, 2018 by pady_1

1 answer

A transistor is operated in common emitter configuration at constant collector voltage $V_c = 1.5 V$ such that a change in the base current from 100 µA to 150 µA produces a change in the collector current from 5 mA to 10 mA. The current gain $\beta$ is:-

asked Jul 25, 2018 by pady_1

1 answer

A photosensitive metallic surface has work function, $hv_0$. If photons of energy $2hv_o$ fall on this surface, the electrons come out with a maximum velocity of $4\times10^6$ m/s. When the photon energy is increased to $5hv_0$, then maximum velocity of photo electrons will be

asked Jul 24, 2018 by pady_1

1 answer

A nucleus represented by the symbol $_{Z}^{A}X$ has :-

asked Jul 24, 2018 by pady_1

1 answer

We consider the radiation emitted by the human body. Which of the following statements is true :

asked Jul 24, 2018 by pady_1

1 answer

The efficiency of carnot engine is 50% and temperature of sink is 500K. If temperature of source is kept constant and its efficiency raised to 60%, then the required temperature of the sink will be : -

asked Jul 23, 2018 by pady_1

1 answer

The width of river is 1 km. The velocity of boat is 5 km/hr. The boat covered the width of river with shortest will possible path in 15 min. Then the velocity of river stream is :

asked Jul 20, 2018 by pady_1

1 answer

$10^{5}$ coloumb charge liberated 1 gm silver (Ag). If now charge is doubled then the amount of liberated Ag will be :

asked Jun 15, 2018 by pady_1

1 answer

A survey was done in all schools of Hyderabad, where each student was asked for their favorite sport. Result of survey is shown in the circle chart. , Which is the least liked sport among students in Hyderabad ?

asked Dec 31, 2015 by pady_1

0 answers

Find the length of a field of area 150 sq. m and breadth 12 m.

asked Dec 31, 2015 by pady_1

0 answers

What is the multiplicative inverse of 0

asked Dec 31, 2015 by pady_1

0 answers

A boy scored 35 \% marks of 900. He fails by 20 marks. What is the pass marks?

asked Dec 31, 2015 by pady_1

0 answers

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The structure of intermediate A in the following reaction is :-

A glass flask of volume $200 \; cm^3$ is completely filled with mercury at $20^{\circ}C$. The amount of mercury that spilt over when the flask is heated to $80^{\circ}C$ is (coefficient of volume expansion for glass $27 \times 10^{-8} /^{\circ}C$, mercury $0.18 \times 10^{-8}/^{\circ}C$) :

Two simple pendulums of lengths $16 l$ and $l$ are in phase at the mean position at a certain time. If $T$ is the time period of shorter pendulum, the minimum time after which they will be again in phase :

Wavelength of light used in optical instrument are $\lambda_1 = 4000 \mathring{A}$ and $\lambda_2 = 5000 \mathring{A}$, then ratio of their respective resolving powers (corresponding to $\lambda_1$ and $\lambda_2$) is :

The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the :

$\displaystyle\lim_{x \to \frac{\pi}{2}} \frac{\cot x - \cos x}{(\pi - 2 x)^3}$ equals

A $25 \;cm$ long solenoid has radius $2\; cm$ and $500$ total number of turns. It carries a current of $15\; A$. If it is equivalent to a magnet of the same size and magnetization $\overrightarrow{M}$ (magnetic moment/volume), then $|\overrightarrow{M}|$ is :

A gaseous hydrocarbon given upon combustion 0.72 g of water and 3.08 g of $CO_2$. The empirical formula of the hydrocarbon is :

If the lines $\frac{x-1}{2} = \frac{y+1}{3} = \frac{z-1}{4}$ and $ \frac{x-3}{1} = \frac{y-k}{2} = \frac{z}{1}$ intersect, then $k$ is equal to

A resistor 'R' and $2 \mu F$ capacitor in series is connected through a switch to 200 V direct supply. Across the capacitor is a neon bulb that lights up at 120 V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed. ($\log_{10} 2.5 = 0.4$)

The correct order of increasing basicity of the given conjugate bases $(R = CH_3)$ is

A charge Q is placed at each of the opposite corners of a square. A charge q is placed at each of the other two corners. If the net electrical force on Q is zero, tthen the Q/q equals

If a line makes an angle of $\frac{\pi}{4}$ with the positive directions of each of $x-axis$ and $y-axis$, then the angle that the line makes with the positive direction of the $z-axis$ is :

A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple i kept hot and the other is kept cold, then, an electrix current will :

If $a^2+b^2+c^2 = -2$ and $f(x) = \begin{vmatrix} 1+a^2x & (1+b^2)x & (1+c^2) x \\ (1+a^2)x & 1+b^2x & (1+c^2)x \\ (1+a^2)x & (1+b^2)x & 1+c^2x \end{vmatrix}$, then $f(x)$ is a polynomial of degree :

Average density of the earth :

The sum of series $\frac{1}{2!} + \frac{1}{4!} + \frac{1}{6!}+... $ is

Which one of the following statements is correct when $SO_2$ is passed through acidified $K_2Cr_2O_7$ solution ?

If Avogadro number NA, is changed from $6.022 \times 10^{23} mol^{–1}$ to $6.022 \times 10^{20} \;mol^{–1}$, this would change :

If $n_1$, $n_2$ and $n_3$ are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by:

A wave travelling in the +ve x-direction having displacement along y-direction as 1m, wavelength $2 \pi m$ and frequency of $\frac{1}{\pi}$ Hz is represented by :

If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q ?

The rate of increase of thermo - e.m.f. with temperature at the neutral temperature of a thermocouple :

The activity of a radioactive sample is measured as N0 counts per minute at t = 0 and N0/e counts per minute at t = 5 minutes. The time (in minutes) at which the activity reduces to half its value is –

A simple pendulum performs simple harmonic motion about x = 0 with an amplitude a and time period T. The speed of the pendulum at $x=a/2$will be :

In the circuit shown, the current through the 4$\Omega$ resistor is 1 amp when the points P and M are connected to a D.C. voltage source. The potential difference between the points M and N is <br>

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:

A transistor is operated in common emitter configuration at constant collector voltage $V_c = 1.5 V$ such that a change in the base current from 100 µA to 150 µA produces a change in the collector current from 5 mA to 10 mA. The current gain $\beta$ is:-

A photosensitive metallic surface has work function, $hv_0$. If photons of energy $2hv_o$ fall on this surface, the electrons come out with a maximum velocity of $4\times10^6$ m/s. When the photon energy is increased to $5hv_0$, then maximum velocity of photo electrons will be

A nucleus represented by the symbol $_{Z}^{A}X$ has :-

We consider the radiation emitted by the human body. Which of the following statements is true :

The efficiency of carnot engine is 50% and temperature of sink is 500K. If temperature of source is kept constant and its efficiency raised to 60%, then the required temperature of the sink will be : -

The width of river is 1 km. The velocity of boat is 5 km/hr. The boat covered the width of river with shortest will possible path in 15 min. Then the velocity of river stream is :

$10^{5}$ coloumb charge liberated 1 gm silver (Ag). If now charge is doubled then the amount of liberated Ag will be :

A survey was done in all schools of Hyderabad, where each student was asked for their favorite sport. Result of survey is shown in the circle chart. , Which is the least liked sport among students in Hyderabad ?

Find the length of a field of area 150 sq. m and breadth 12 m.

What is the multiplicative inverse of 0

A boy scored 35 \% marks of 900. He fails by 20 marks. What is the pass marks?