Recent questions tagged difficult

Define the term electrical resistivity of a material. Write the S.I units. Derive an expression for the resistivity of a metal in terms of number density and mass of free electrons present in it .

asked Jul 1, 2015 by meena.p

1 answer

By what percentage will have the illumination of amp decrease if the current drops by $20\%$ ?

asked Jun 30, 2015 by meena.p

1 answer

A current of $1.0\;mA$ s flowing through a potentio meter wire of length $4\;m$ and of resistance $4 \Omega$ ,find the potential gradient of the potentio meter wire .

asked Jun 30, 2015 by meena.p

1 answer

When is the Wheatstones bridge most sensitive ?

asked Jun 30, 2015 by meena.p

1 answer

Resistance of a human body is of the order of $10 \;k \Omega$ . Why does one experience a strong wire of say $240\;V$ supply ?

asked Jun 30, 2015 by meena.p

1 answer

If P.d applied across a conductor is increased to $2V$ ,how will the drift velocity of the electrons change?

asked Jun 30, 2015 by meena.p

1 answer

If the length of a wire conductor is doubled by stretching it, keeping the p.d across it constant, by what factor does the drift speed of electrons charge ?

asked Jun 30, 2015 by meena.p

1 answer

A paisa coin is made up of Al-my alloy and weights $0.75\;g$ It has a square shape and its diagonal measures $17\;mm$ It is electrically neutral and contains equal amounts of positive and negative charges. Treating the paisa coins made up only $Al$, find the magnitude of equal number of positive and negative charges. What conclusion do you draw from this magnitude ?

asked Apr 29, 2015 by meena.p

1 answer

It is believed that protons and neutrons (which constitute nucli of or ordinary matter) are themseleves built out of more elementary units called quarks. A proton and a neutron consists of there quarks each. Two type of quarks, the so called 'up' quark (denoted by u) of charge $+\bigg( \large\frac{2}{3}$$e\bigg)$ and the down quark denoted by of charge $\bigg( \large\frac{-1}{3}$$e\bigg)$, together with electricity build up an ordinary matter. (quarks of other types have also been found which give rise to different ususual varieties of matter. ). Suggest a possible quark composition of a proton and neutron .

asked Apr 29, 2015 by meena.p

1 answer

The electric field component in the following figure are $Ex = \alpha x^{1/2}, E_y =0, E_z=0$ in which $\alpha =800 NCm6{-1/2}$ Calculate the charge within the cube. Assume $a= 0.1\;m$

asked Apr 28, 2015 by meena.p

1 answer

The electric field component in the following figure are $Ex = \alpha x^{1/2}, E_y =0, E_z=0$ in which $\alpha =800 NCm6{-1/2}$ Calculate the flux $\phi _2$ through the cube

asked Apr 28, 2015 by meena.p

1 answer

Two points charges $q_1$ anb $ q_2$ are located at points $(a,0,0)$ and $(0,b,0)$ respectively . Find the electric field bue to these charges at the point $(0,0,0)$

asked Apr 28, 2015 by meena.p

1 answer

Two points charges $+Q$ and $+4Q$ are seperated by a distance of $6a$ . find the point on the line joining the two charges where the electric field is zero.

asked Apr 27, 2015 by meena.p

1 answer

How many electrons must be removed from a ball of mass $3.2 \;g$ so that it may fleat in an electric field of intensity $10^{10}N/C$ directed upwards?

asked Apr 27, 2015 by meena.p

1 answer

An electron and proton are freely located in an electric field. Compare (i) electric force on them (ii) the acceleration on them

asked Apr 24, 2015 by meena.p

1 answer

This figure represents the electric lines of force at constant potentials, Shown in constant,Potentials, shown in bracket . At which point A , B and C is the electric field maximum ?

asked Apr 24, 2015 by meena.p

1 answer

A cylinder of radius R and length L is placed in a uniform electric field parallel to the axis of a cylinder. What is the electric flux through the whole cylinder ?

asked Apr 24, 2015 by meena.p

1 answer

If a point charge be rotated in an arc of radius r around a change q, what will be the workdone ? explain

asked Apr 24, 2015 by meena.p

1 answer

If a point charge be rotated in an arc of radius r around a change q, what will be the workdone ? explain

asked Apr 24, 2015 by meena.p

1 answer

A is a metallic sphere placed between two charged metallic plates. A student draws the line of force as shown in the figure . Is he correct ?

asked Apr 24, 2015 by meena.p

1 answer

A proton and an electron are placed freely in an electric field. Which of the partides will have greater acceleration and why ?

asked Apr 24, 2015 by meena.p

1 answer

A man in an insulted metallic cage does not receive a shock, even when the cage is connected to a high voltage source . Whay ?

asked Apr 24, 2015 by meena.p

1 answer

What is the solid subtended by a hemisphere at a point inside it ?

asked Apr 22, 2015 by meena.p

1 answer

Quarles are building blocks of nucleus and posses fractional electronic charge. Does this discovers violate the principal of quantisation of charge ?

asked Apr 22, 2015 by meena.p

1 answer

From the number of electrons in $lc$ of negative charge.

asked Apr 22, 2015 by meena.p

1 answer

The force on an electron kept in an electric field in a particular direction is F. What will be the magnitude and direction of the force experienced by a proton kept at the same point in the filed ? Mass of the proton is about $1836$ times the mass of the electron

asked Apr 22, 2015 by meena.p

2 answers

The electric field in a certain region of space is given by $E= \hat i +2 \hat j + 3\hat k Nc$. Calculate the electric flux over the area given by $S= 3 \hat i + 4 \hat j \;m^2$

asked Apr 22, 2015 by meena.p

1 answer

Two pipes can fill a cistern in 8 hours and 7 hours respectively. The pipes are opened simultaneously and it is found that due to leakage in the bottom it took 16 minutes more to fill the cistern. When the cistern is full, in what time the leak empty it ?

asked Dec 8, 2014 by pady_1

0 answers

If two pipes function simultaneously, the reservoir will be filled in 6 hours. One pipe fills the reservoir 5 hours faster than the other. How many hours does it take the second pipe to fill the reservoir ?

asked Dec 8, 2014 by pady_1

1 answer

Two pipes P and Q can fill a tank in 22.5 hours and 18 hours respectively. If both the pipes are opened simultaneously, how much time will be taken to fill the tank ?

asked Dec 8, 2014 by pady_1

0 answers

A house is to be constructed in 46 days and 117 men were set to work, each working 8 hours a day. After 33 days, 4/7 of the work is completed. How many additional men may be employed so that the work may be completed in time, each man now working 9 hours a day?

asked Dec 8, 2014 by pady_1

0 answers

The sum of two number is 20 and their difference is 8. Find their product.

asked Dec 8, 2014 by pady_1

0 answers

The difference of the squares of two consecutive even numbers is 96, What is the sum of those numbers?

asked Dec 8, 2014 by pady_1

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The sum of squares of three numbers is 764 and sum of their products taken two at a time is 500. What is their sum?

asked Dec 8, 2014 by pady_1

1 answer

The difference between a two digit number and the number obtained by interchanging the digits is 72. What is the difference between the digits of the number?

asked Dec 8, 2014 by pady_1

1 answer

If the sum of 1st n integers is 55 then what is n?

asked Dec 8, 2014 by pady_1

0 answers

The average weight of 3 packets A, B and C is 84 kg. Another packet D added into the group and the average now becomes 80 kg. If another packet E, whose weight is 3 kg more than that of D, replaces A then the average weight of B, C, D and E becomes 79 kg. The weight of A is:

asked Dec 8, 2014 by pady_1

0 answers

A batsman in his 13th innings makes a score of 77 and there by increases his average by 4. what is his average after the 13th innings?

asked Dec 8, 2014 by pady_1

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Find the average of first 35 natural numbers.

asked Dec 8, 2014 by pady_1

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Three numbers which are co-prime to each other are such that the product of the first two is 1102 and that of the last two is 2146. The sum of the three numbers is:

asked Dec 8, 2014 by pady_1

0 answers

If the sum of two numbers is 72 and the H.C.F. and L.C.M. of these numbers are 6 and 60 respectively, then the sum of the reciprocals of the numbers is equal to:

asked Dec 8, 2014 by pady_1

0 answers

The H.C.F. of 6/7 , 14/25 , 18/35 and 21/40 is:

asked Dec 8, 2014 by pady_1

0 answers

Three numbers are in the ratio 2:3:4 and their LCM is 600. Their HCF is

asked Dec 8, 2014 by pady_1

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The H.C.F. and L.C.M. of two numbers are 4 and 2200 respectively. If the first number is divided by 5, the quotient is 20. The second number is:

asked Dec 8, 2014 by pady_1

0 answers

The L.C.M. of two numbers is 140 and their H.C.F. is 5. If the sum of the numbers is 55. Then their difference is:

asked Dec 8, 2014 by pady_1

1 answer

The L.C.M. of 2/3, 5/6, 2/9, 8/27 is:

asked Dec 8, 2014 by pady_1

0 answers

The H.C.F. of 3/9, 12/13 and 9/17 is:

asked Dec 8, 2014 by pady_1

0 answers

What is the next year which have the calender as year 1990?

asked Dec 8, 2014 by pady_1

0 answers

A watch which gains uniformly, is 6 min. slow at 8 o'clock in the morning Sunday and it is 6 min. 48 sec. fast at 8 p.m. on following Sunday. When was it correct?

asked Dec 8, 2014 by pady_1

0 answers

Three clocks were set to true time and starts to run together, makes a beep sound at intervals of 8,10 and 12 minutes respectively. In 2 days, how many times do they will make the sound together ?

asked Dec 8, 2014 by pady_1

1 answer

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