An electric field of $1500\, V/m$ and a magnetic field of $0.40\, Wb/m^2$ act on a moving electron. The minimum uniform speed along a straight line the electron could have is

$A$ particle of mass $m$,charge $Q$,and kinetic energy $K$ enters a transverse uniform magnetic field of induction $B$. After $3$ $seconds$,the kinetic energy of the particle will be .......$K$.

An electron of mass $9 \times 10^{-31} \ kg$ and charge $1.6 \times 10^{-19} \ C$ moving with a velocity of $10^6 \ ms^{-1}$ enters a magnetic field normally and describes a circle of radius $10 \ cm$. The intensity of the magnetic field is:

When an electron placed in a uniform magnetic field is accelerated from rest through a potential difference $V_1$,it experiences a force $F$. If the potential difference is changed to $V_2$,the force experienced by the electron in the same magnetic field is $2F$. Then,the ratio of potential differences $\frac{V_2}{V_1}$ is:

$A$ uniform magnetic field $B$ and a uniform electric field $E$ act in a common region. An electron is entering this region of space. The correct arrangement for it to escape undeviated is

An electron having charge $1.6 \times 10^{-19} \, C$ and mass $9 \times 10^{-31} \, kg$ is moving with $4 \times 10^6 \, m/s$ speed in a magnetic field of $2 \times 10^{-1} \, T$ in a circular orbit. The force acting on the electron and the radius of the circular orbit are: