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LLM · Positional encodings: relative & ALiBi

11 questions · 25 marks · 3 papers

Answer key

Indian Institute of Technology Madras

BS Degree Programme · Examination & Study Paper

Large Language Models

Positional encodings: relative & ALiBi

Official Paper

Examination Instructions & Guidelines

Solve on notebook/paper first before checking solutions.
MCQ: Exactly 1 option is correct. Negative marking applies.
MSQ: One or more options correct. Select all to score.
NAT: Numerical response. No negative marking.
Scientific calculator allowed for all calculations.
Official answer key is sealed at the end of this sheet.

Quiz 1 · 26 Oct 2025 (AN)Quiz 1

Q1MCQ2 Marks·Choose one option
Key ↓
Which of the following is true regarding sinusoidal encoding?
1. AThe encoding vector of words present at even positions in the given text sequence uses sine, and the encoding vector of words present at odd positions uses cosine.
2. BThe encoding vector of words present at odd positions in the given text sequence uses sine, and the encoding vector of words present at even positions uses cosine.
3. CThe encoding vector for each word position contains values computed using both sine (for even dimensions) and cosine (for odd dimensions).

End Term · 31 Aug 2025 (FN)End Term

Read the passage below, then answer Q2–Q5
Based on the above data, answer the given subquestions.
Q2MCQ1 Mark·Choose one option
Asked 2 times Key ↓
1. A(0, 1, 2, 3, 4)
2. B(-1, 0, 1, 2, 3)
3. C(-2, -1, 0, 1, 2)
4. D(-3, -2, -1, 0, 1)
Q3MCQ1 Mark·Choose one option
Asked 2 times Key ↓
1. A
2. B
3. C
4. D
Q4NAT3 Marks·Write the number
Asked 2 times Key ↓
Your answer:
Q5NAT3 Marks·Write the number
Asked 2 times Key ↓
Your answer:

End Term · 31 Aug 2025 (AN)End Term

Q6MSQ3 Marks·Choose all correct options
Key ↓
In Transformer models that use relative position embeddings (such as in Transformer-XL or T5), clipping is often applied to the relative position indices. Which of the following statements about clipping in relative position embeddings are correct?
1. AClipping ensures that very large relative distances are mapped to a fixed maximum distance.
2. BWithout clipping, the model would require embeddings for every possible relative distance, which is infeasible for long sequences.
3. CClipping increases the precision of embeddings for large relative distances.
4. DClipping introduces an upper bound k such that all distances greater than k are mapped to the same index.
Read the passage below, then answer Q7–Q11
Based on the above data, answer the given subquestions.
Q7MCQ2 Marks·Choose one option
Asked 2 times Key ↓
1. A(0, 1, 2, 3, 4, 5)
2. B(-1, 0, 1, 2, 3, 4)
3. C(-3, -2, -1, 0, 1, 2)
4. D(-2, -1, 0, 1, 2, 3)
Q8MCQ2 Marks·Choose one option
Asked 2 times Key ↓
1. A[−0.4,−0.4,−0.4,−0.4]
2. B[−0.1,−0.1,−0.1,−0.1]
3. C[−0.8,−0.8,−0.8,−0.8]
4. D[−0.2,−0.2,−0.2,−0.2]
Q9NAT3 Marks·Write the number
Asked 2 times Key ↓
Your answer:
Q10NAT2 Marks·Write the number
Asked 2 times Key ↓
Your answer:
Q11NAT3 Marks·Write the number
Key ↓
Your answer:

Official Key

Master Answer Key & Explanations

Official answer keys from IIT Madras BS past papers. Click any question to review.

Reveal Key

Q1C

Q2C

Q3B

Q410

Q521.3 to 22

Q6A, B, D

Q7D

Q8C

Q915.2

Q1023.7 to 24.3

Q1139

Questions and answer keys are reproduced from the official IIT Madras BS papers. Topics and repeated question types are BTechi’s own grouping. BTechi is not affiliated with IIT Madras.