Question -
Answer -
(i) When TR curve is positively sloped straight line, MR is a horizontal line. MR coincides with the demand curve. Price or AR is constant at each level of output.
When AR is constant, MR is also constant.
(ii) When TR is a horizontal straight line, MR is zero. It is because horizontal TR means when price falls, quantity demanded rises in the same proportion. Thus, MR is zero. MR curve coincides with the x-axis