The huge potential of solar energy and increasing demand of energy, made researchers to work on solar photovoltaic systems. In this paper, experimental investigations and exergy based thermodynamic assessment of 1 kW solar photovoltaic (SPV) plant have been carried out. The system is installed at Amity University Gurgaon, India. With the aim to assess the performance/efficiency of the plant, two exergy techniques have been applied based on concepts of thermodynamics and chemical/photonic energy of input solar insolation. The input energy and exergy at different wavelengths ranging from 0.4 µm-0.7 µm have been formulated and illustrated. The electrical and operating parameters of SPV plant includes short-circuit current, open-circuit voltage, temperature of photovoltaic (PV) modules, and fill factor are found, carrying an experiment on a sunny day of 5th October 2017. The variations of electrical exergy input at different fill factors have been computed which signifies its role in characteristic behavior of PV system. The energy/exergy efficiencies are found to be between 7.76% to 9.98% and 9.86% to 11.63% whereas the photonic energy/exergy efficiencies are found to be between 4.85% to 11.24% and 6.08% to 12.89%. It is also found that the temperature of SPV plays a vital role on exergy efficiency and it can be improved with a mechanism which removes the generated heat from the system. With the experimental results, it can be noticed that the exergy loss increases as the temperature of SPV module goes up.