The given circuit is an inverting op-amp amplifier with first-order RC circuit. Use following steps to determine voltage across capacitor when step input is applied at inverting terminal of op-amp.

Step (1): Determine voltage at the output terminal of op-amp. Use virtual ground concept and use KCL to determine output voltage of op-amp.

Step (2): Now calculate voltage across capacitor at t = 0 and infinite.

Step (3): next determine time-constant of the RC circuit.

Step (4): Voltage across capacitor at t = 0, infinite and time-constant of the RC circuit can be used to write voltage across capacitor with respect to time.