An ideal coil of $10 \, H$ is connected in series with a resistance of $5 \, \Omega$ and a battery of $5 \, V$. $2 \, s$ after the connection is made,the current flowing (in ampere) in the circuit is:

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

The number of subsets of $\{1, 2, 3, \ldots, 9\}$ containing at least one odd number is

$A$ telescope has an objective lens of focal length $200 \ cm$ and an eyepiece with focal length $2 \ cm$. If this telescope is used to see a $50 \ m$ tall building at a distance of $2 \ km$,what is the height of the image of the building formed by the objective lens in $cm$?

$A$ neutron moving with velocity $u$ collides elastically with an atom of mass number $A$. If the collision is head-on and the initial kinetic energy of the neutron is $E$,then the final kinetic energy of the neutron after the collision is

The equation of the circle whose diameter is the common chord of the circles $x^2+y^2+2x+3y+2=0$ and $x^2+y^2+2x-3y-4=0$ is