Question

Assertion$\left(A\right)$: If an electron, while coming vertically from outerspace, enter the earth's magnetic field, it is deflected towards west.
Reason$\left(R\right)$: Electron has negative charge.

• A. Both $A$ and $R$ are true and $R$ is correct explanation of $A$
• B. Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$
• C. $A$ is true but $R$ is false
• D. $A$ is false but $R$ is true

Answer 1

The correct option is A Both $A$ and $R$ are true and $R$ is correct explanation of $A$

We know that the direction of the earth's magnetic field $\left(\overrightarrow{B}\right)$ is towards north and the velocity of electron $\left(\overrightarrow{v}\right)$ is vertical downwards.
Using $\overrightarrow{F}=q(\overrightarrow{v}\times \overrightarrow{B})$ and right hand thumb rule, an electron coming from outer space will be deflected towards west.