IBM A1000-136 Intermediate Practice Exam: Medium Difficulty 2025

A quantum developer is designing a circuit to prepare a superposition state where measuring |0⟩ should occur with 75% probability and |1⟩ with 25% probability. Which approach correctly achieves this state preparation?

A research team is implementing a quantum algorithm on IBM Quantum hardware and notices that their multi-qubit gate operations are experiencing significantly higher error rates than expected. They need to optimize their circuit design. What is the MOST effective strategy to reduce errors?

A quantum programmer is implementing the Quantum Fourier Transform (QFT) as part of Shor's algorithm. For a 4-qubit system, approximately how many controlled rotation gates are required in the standard QFT implementation?

A developer needs to measure only a subset of qubits in a quantum circuit while leaving others unmeasured for subsequent operations. Using Qiskit on IBM Quantum Platform, what happens to the unmeasured qubits after a partial measurement is performed?

An organization is evaluating quantum algorithms for optimization problems. They have a portfolio optimization problem with 50 assets and need to select 10. Which quantum approach would be MOST suitable for this constrained optimization problem on current NISQ-era devices?

A quantum circuit designer is experiencing phase kickback in their implementation of a quantum oracle. The oracle should mark a specific state |x⟩ by flipping its phase. Which qubit configuration and gate setup correctly implements phase kickback for this oracle?

A team is using IBM Quantum Composer to build a circuit that implements a simple quantum error detection code. They want to detect bit-flip errors on a single data qubit using two ancilla qubits. What is the minimum circuit structure required?

A quantum developer is using Qiskit Runtime on IBM Quantum Platform to execute a variational algorithm. They observe that the classical optimization loop is taking significantly longer than the quantum circuit execution. What feature of Qiskit Runtime would BEST address this performance bottleneck?

A researcher is implementing Grover's algorithm to search an unsorted database of N=256 items. Approximately how many iterations of the Grover operator should be applied to maximize the probability of finding the target item?

A quantum circuit contains a sequence of gates: H gate on qubit 0, CNOT with control=0 and target=1, then another CNOT with control=1 and target=0. Starting from |00⟩, what is the resulting state after these operations?