Question regarding Transresistance Amplifier Circuit
The current is is equal to the current moving through the resistor. This is why we called a virtual ground, the voltage of the negative terminal is the same as the positive terminal if in negative feedback, but no current flows into the terminal in the case of an ideal op amp such as this one.

Because of this the currents are equal and the current flowing through the resistor can only flow through the diode.

There is still a voltage difference in the diode, however the op amp is continually driving the diodes voltage to 0 volts.