When Total Utility (TU) is at its maximum, Marginal Utility (MU) is:
(a) Positive
(b) Zero
(c) Negative
(d) Infinite

Question

Accepted Answer

Total Utility is the running sum of all the Marginal Utilities consumed so far. As long as each additional unit still adds some positive Marginal Utility, TU keeps climbing. The moment Marginal Utility becomes zero, the next unit adds nothing further to TU, so TU stops rising and reaches its peak at exactly that point — this is called the point of satiety. Option (a), positive MU, is what happens before the maximum, while TU is still rising, not at the maximum itself. Option (c), negative MU, is what happens after the maximum, when TU has already started falling because further consumption is actively causing disutility. Option (d), infinite, has no meaning in this context — utility values are finite. Only option (b) correctly describes the exact turning point where TU stops increasing and is at its highest value.

✓Final answer

(b) Zero — TU is maximum exactly at the unit where MU falls to zero (the point of satiety); TU falls once MU turns negative.

Same / Similar Concept — real previous-year questions on the same or a closely similar concept, not this exact question.

CBSE 2023Set ANNUAL1 markMCQ
$Q. MU of the commodity becomes negative when TU of a commodity is ______.$
(a) rising
(b) constant
(c) falling
(d) zero
›Reveal solutionSolution
MU of a commodity becomes negative when its TU is falling — that is, only after the point of maximum total utility (saturation) has been crossed.

Marginal utility is the change in total utility from consuming one additional unit of a commodity (MU of the nth unit = TU of n units minus TU of (n-1) units). As a consumer keeps consuming more units:

While TU rises, MU is positive (though diminishing).

When TU is maximum, MU is zero — this is the point of satiety.

When TU falls, MU turns negative, because the extra unit now causes disutility (e.g. the 6th glass of water after thirst is quenched).

So negative MU is associated only with the stage where total utility has begun to decline.

✓Final answer
$MU of the commodity becomes negative when TU of a commodity is falling .$
CBSE 2022Set ANNUAL1 mark
$Q. Give economic terms: Additional utility derived by a consumer from an additional unit consumed.$
›Reveal solutionSolution
The economic term is Marginal Utility (MU) — the extra satisfaction a consumer derives from consuming one additional unit of a commodity.

Utility is the want-satisfying power of a good. Two related measures are used:

Total Utility (TU) — the total satisfaction obtained from consuming all the units of a commodity.

Marginal Utility (MU) — the addition made to total utility by consuming one more unit, i.e. MU = change in TU / change in units consumed.

Since the definition given points to the additional satisfaction from an additional unit, the correct term is marginal utility. As more units are consumed, MU generally falls (the law of diminishing marginal utility).

✓Final answer
$Additional utility from an additional unit consumed = Marginal Utility (MU)$

> [!ANSWER]
> (b) Zero — TU is maximum exactly at the unit where MU falls to zero (the point of satiety); TU falls once MU turns negative.

Q.When Total Utility (TU) is at its maximum, Marginal Utility (MU) is:

Concept understanding — Total Utility and Marginal Utility

Q.When Total Utility (TU) is at its maximum, Marginal Utility (MU) is:

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