EasyAssistant Engineer (Electrical), Class-2, Road and Building Department2025✓ Editorially verified

Determine the discrete−time signal: x(n) = 1 for n ≥ 0 and x(n) = 0 for n < 0.

⚑ Report issue

Found a wrong answer, translation, image or source problem? Send it to editorial review.

Answer & Explanation

Correct AnswerD. Unit step sequence

Quick Explanation

The sequence defined as 1 for n≥0 and 0 for n<0 is the discrete-time unit step u[n]. It switches from 0 to 1 at n=0 and remains at 1 thereafter.

Formula / Key Relation

u[n] = {1, n ≥ 0

{0, n < 0

δ[n] = u[n] − u[n−1]

Detailed Explanation

Concept & Reasoning

The unit impulse δ[n] is nonzero only at n=0, whereas the unit step u[n] remains one for all nonnegative n. A unit ramp grows with n. These distinctions are fundamental in convolution and system-response problems.

How to Solve It in the Exam

One at and after zero → unit step.

Important Exam Point

Use δ[n] only for a single non-zero sample at n=0.

Related Revision Path

This question sits in the revision path Signals and Systems → Discrete-Time Signals → Elementary Sequences .

Quick Trick

One at and after zero → unit step.

Common Mistake

Confusing unit step with unit impulse.

Exam Tip

Use δ[n] only for a single non-zero sample at n=0.

SEO + Knowledge GraphRelated PYQs & Exam ContextExam path, knowledge path and deeper practice links.

Exam Path

Knowledge Path

Study concept · Unit Step Sequence →Practice concept Practice topic

10Previous Exam Appearances

6All Related Questions

87Content Quality

Previous Exam Appearances

Assistant Engineer (Electrical), Class-2, Road and Building Department2025Q. 179