. A current through a horizontal powerline flows in west to east direction. What is the direction of magnetic field at a point, when viewed from the west end? * a) clockwise
b) anti- clockwise
c) parallel to the wire
d) towards east

c) parallel to the wire

Explanation:

The concept is based on right-hand thumb rule that states that the thumb points in the direction of the current and the fingers will represent the direction of the lines of magnetic force.

As the current is moving in the east-west direction. Using the right-hand thumb rule, the direction of the magnetic field at a point below the wire is from north to south. So, when viewed from the west end, the magnetic field at a point will be anti- clockwise.

Hence, the correct answer is "b) anti- clockwise".

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.