1Z0-1127-25 Practice Question: Building LLM Applications with RAG and Vector Search
A RAG application is hallucinating because the LLM receives irrelevant context from the retrieval step, even when topK is set to 3. Which strategy would best reduce hallucination by improving the relevance of retrieved documents?
⚠ Common exam trap
Oracle often tests the misconception that simply adjusting retrieval parameters (like chunk size or topK) can fix relevance issues, when the real solution is a dedicated reranking step that re-evaluates relevance with a more powerful model.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a reranking step after retrieval to select the most relevant chunks
Adding a reranking step after retrieval directly addresses the core issue: even with a low topK, the initial retrieval may return chunks that are semantically similar but not precisely relevant to the query. Reranking uses a cross-encoder model to score each retrieved chunk against the query, reordering them so that only the most contextually relevant chunks are passed to the LLM. This reduces the chance of the LLM receiving irrelevant context, thereby minimizing hallucination.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Reduce the chunk size to one sentence per chunk
Why it's wrong here
May lose necessary context.
- ✓
Add a reranking step after retrieval to select the most relevant chunks
Why this is correct
Reranking improves the relevance of the final context set.
- ✗
Implement a query rewriting mechanism
Why it's wrong here
Query rewriting may help but does not directly fix irrelevant retrieval.
- ✗
Increase topK to 10 to provide more context
Why it's wrong here
More context often includes more irrelevant information, potentially increasing hallucination.
Go deeper
Related to this question
About these practice questions
This 1Z0-1127-25 question is part of Courseiva's 768-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 1Z0-1127-25 practice question is part of Courseiva's free Oracle certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 1Z0-1127-25 exam.