If we introduce a battery, the properties of the n-type and the p-type area will change. If the polarity of the battery is placed as in the picture, the negative electrons will move to the right towards the positive pole of the battery. The reason for this movement is because electrical charges of opposite sign attract. In the p-type area the holes will move to the left towards the other, the negative pole of the battery. The gap that is created in the proximity of the P-N junction prevents the current from flowing in the circuit and the lamp will not shine. In this case, when the battery is applied with the positive pole versus the n-type area, the diode is said to be reversed biased. This means that no current is present in the circuit.