Time taken to complete a zero order reaction is . . . . . . .

For a zero order reaction,the plot of concentration of reactant $vs$ time is (Hint: Consider the intercept on the concentration axis)

For a reaction,doubling the concentration of the reactant doubles the half-life period. What is the order of the reaction?

The time for the half-life period of a certain reaction $A \rightarrow \text{Products}$ is $1 \ hr$. When the initial concentration of the reactant $A$ is $2.0 \ mol \ L^{-1}$,how many hours does it take for its concentration to decrease from $0.50 \ mol \ L^{-1}$ to $0.25 \ mol \ L^{-1}$ if it is a zero-order reaction?

Give examples of zero order reactions.

Which of the following is correct with respect to the graph given?
$[R] = \text{Concentration at time } 't'$
$[R]_0 = \text{Initial concentration}$