IBM A1000-112: Assessment: Fundamentals of Quantum Computation Using Qiskit v0.2x Developer Intermediate Practice Exam: Medium Difficulty 2025

A quantum developer needs to create a circuit that prepares a Bell state |Φ+⟩ = (|00⟩ + |11⟩)/√2 and then measures both qubits. Which sequence of Qiskit operations correctly implements this?

A developer is implementing a quantum circuit using Qiskit v0.2x and needs to apply a rotation around the Y-axis by π/4 radians to qubit 2, followed by a controlled-Z gate between qubits 1 (control) and 2 (target). Which code snippet correctly implements this?

When implementing Grover's algorithm for a 3-qubit search problem with a single marked state, how many iterations of the Grover operator should be applied to maximize the probability of measuring the marked state?

A developer wants to execute a quantum circuit on a real IBM quantum backend but first needs to transpile it to match the hardware topology. The backend has a linear connectivity: q0-q1-q2-q3. The circuit contains a CNOT(q0, q3). What will the transpiler primarily need to do?

A quantum circuit implements a phase oracle for Grover's algorithm that marks the state |101⟩. Which combination of gates correctly implements this oracle?

A developer is analyzing measurement results from a quantum circuit executed 1024 times. The results show counts {'00': 256, '01': 256, '10': 256, '11': 256}. What quantum state was most likely measured?

When using Qiskit's QuantumCircuit.decompose() method on a Toffoli (CCX) gate, what is the primary reason for decomposition in the context of running on quantum hardware?

A developer is implementing the Quantum Fourier Transform (QFT) on 3 qubits in Qiskit. After applying all Hadamard and controlled phase rotation gates, what additional operation is necessary to complete the standard QFT implementation?

A quantum developer needs to simulate a circuit with noise to better predict real hardware performance. They want to add depolarizing error with probability 0.01 to all single-qubit gates and probability 0.05 to all two-qubit gates. Which Qiskit component should they use?

A developer is optimizing a variational quantum algorithm using Qiskit. The circuit has 5 parameterized rotation gates. After measuring 8192 shots, they compute the expectation value. To reduce the number of circuit executions during optimization while maintaining reasonable accuracy, which approach should they consider?