PCEP Computer Programming and Python Fundamentals Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  ValueError

  Why this is correct

  math.sqrt() raises ValueError for negative arguments because it cannot return a real square root; it does not return a complex number or NaN. The constraint in the stem is the negative input -1, which triggers this specific exception rather than TypeError or ZeroDivisionError.

• ✗

  NaN

  Why it's wrong here

  math.sqrt raises a ValueError for negative arguments rather than returning NaN; NaN arises from operations like math.sqrt of a float NaN or 0.0/0.0. It is tempting because NaN is the IEEE 754 result for invalid floating-point operations, but Python's math module raises instead.

• ✗

  A complex number

  Why it's wrong here

  math.sqrt returns a float and raises ValueError on negative input; complex results require cmath.sqrt. It is tempting because mathematically the square root of -1 is imaginary, but Python's math module deliberately rejects negative arguments instead of returning a complex type.

• ✗

  AttributeError

  Why it's wrong here

  Raises ValueError, since math.sqrt cannot accept negative reals; AttributeError means the attribute does not exist on the module. It tempts because misspelling a function name, such as math.sqrtt, genuinely produces AttributeError, so that error type is plausible when the module itself is fine.

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