List of practice Questions

The force of interaction between two charges $q_{1}=6\, \mu C$ and $q_{2}=2\, \mu C$ is $12\, N$. If charge $q=-2\, \mu C$ is added to each of the charges, then the new force of interaction is
A charge of $10^{-9} C$ is placed on each of the $64$ identical drops of radius $2\, cm$. They are then combined to form a bigger drop. Its potential will be
An electric dipole has the magnitude of its charge as $q$ and its dipole moment is $p$. It is placed in a uniform electric field $E$. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively
Each capacitor shown in figure is $ 2\mu F $ . Then the equivalent capacitance between A and B is
Two plates of a parallel plate capacitor of capacity $ 50\mu F $ are charged by a battery to a potential of 100 V. The battery remains connected and the plates are separated from each other so that the distance between them is doubled. The energy spent by the battery in doing so, will be
A bullet of mass $2g$ is having a charge of $ 2\mu C $ . Through what potential difference must it be accelerated, starting from rest, to acquire a speed of $10 \,m/s$?
The electrostatic potential of a uniformly charged thin spherical shell of charge $Q$ and radius $R$ at a distance $r$ from the centre is
A capacitor is connected to .a cell of emf E having someJntemal resistance r. The potential difference across the:
A capacitor having capacity of $2.0 \,\mu$ F is charged to $200 \,V$ and then the plates of the capacitor are connected to a resistance wire. The heat produced in joule will be
Electric field and potential inside hollow charged conducting sphere are respectively where $q$ and $r$ are the charge and radius of given sphere
The average weight of $25$ boys was calculated to be $78.4\, kg$. It was later discovered that one weight was misread as $69$ kg instead of $96 \,kg$. The correct average is
The mean and standard deviation of $100$ observations were calculated as $40$ and $5.1$, respectively by a student who took by mistake $50$ instead of $40$ for one observation. Find the correct standard deviation.
The mean deviation from the median of the following set of observations 5, 3, 9, 12, 3, 10, 12, 21, 18, 12, 21 is
The mean marks of 120 students is 20. It was later discovered that two marks were wrongly taken as 50 and 80 instead of 15 and 18. The correct mean of marks is
The mean of $100$ observations is $50$ and their standard deviation is $5$. The sum of all squares of all the observations is
The mean of 12 numbers is 24. If 5 is added in every number, the new mean is
The mean of $5$ observations is $4.4$ and their variance is $8.24$. If three of the observations are $1$, $2$ and $6$, find the other two observations.
The mean of the first n terms of the A.P. (a + d) + (a + 3d) + (a + 5d) + .... is
The mean of the given data is $30$. If total data is $70$, then missing numbers are
The mean of two samples of size 200 and 300 were found to be 25, 10 respectively. Their standard deviations were 3 and 4 respectively. The variance of combined sample of size 500 is
The mean weight of a group of 10 items is 28 and that of another group of n items is 35. The mean of combined group of 10 + n items is found to be 30. The value of n is
The most stable measure of central tendency is
$ C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}OH $ and $ {{H}_{3}}CC{{H}_{2}}OC{{H}_{3}} $ are:
Number of stereoisomers of lactic add is
$0.92 \,g$ of an organic compound was analysed by combustion method. The mass of the $U$-tube increased by $1.08 \,g$. What is the percentage of hydrogen in the compound?