Viruses behave as non-living entities because outside the host cell they:

Which of the following is not correct?

The cathode of a photoelectric cell is changed from a work function $W_1$ to $W_2$ $(W_2 > W_1)$. If the photoelectric currents before and after the change are $I_1$ and $I_2$ respectively,and all other conditions remain constant,then which of the following is true? (Assume $hv > W_2$)

The oxide of nitrogen formed by thermal decomposition of $NH_4NO_3$ is

In $YDSE$ with two identical slits, when the upper slit is covered with a transparent sheet of mica, the second-order minima is observed above the center of the screen and the second-order maxima below it. Which of the following cannot be a possible value of the phase difference caused by the mica sheet?

Suppose $A$ and $B$ are two points on the line $2x-y+3=0$ and $P(1,2)$ is a point such that $PA=PB$. Then,the mid-point of $AB$ is