The direction ratios of the normal to the plane passing through $(0,0,1)$, $(0,1,2)$, and $(1,0,3)$ are

From a point on the level ground,the angle of elevation of the top of a pole is $30^{\circ}$. On moving $20 \ m$ nearer to the pole,the angle of elevation becomes $45^{\circ}$. The height of the pole (in metres) is:

If $a, b, c$ are in $AP$,and $b-a, c-b, a$ are in $GP$,then $a: b: c$ is

Charge passing through a conductor of cross-section area $A=0.3 ~m^2$ is given by $q=3 t^2+5 t+2$ in coulomb,where $t$ is in second. What is the value of drift velocity at $t=2 ~s$ ? (Given,$n=2 \times 10^{25} / m^3$ )

When a system is taken from state $i$ to state $f$ along the path $iaf,$ it is found that $Q = 50 \, cal$ and $W = 20 \, cal$. Along the path $ibf$,$Q = 36 \, cal$. Work done along the path $ibf$ will be ........... $cal$.

The least count of a stopwatch is $\frac{1}{5} \, s$. The time of $20$ oscillations of a pendulum is measured to be $25 \, s$. The maximum percentage error in the measurement of time will be ..... $\%$