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जुलै ९, २०२३ पासूनच्या पोेस्ट दाखवत आहे

what are the steps through which a refrigerant goes in one complete cycle of refrigeration.

In one complete cycle of refrigeration, the refrigerant, a liquid such as fluorinated hydrocarbon, goes through the following steps. The refrigerant in the closed tube passes through the nozzle and expands, into a low pressure area. This adiabatic expansion results in reduction in pressure and temperature of the fluid and the fluid turns into a gas. The cold gas is in thermal contact with the inner compartment of the fridge. Here it absorbs heat at constant pressure from the contents of the fridge. The gas passes to a compressor where it does work in adiabatic compression. This raises it's temperature and converts it back into a liquid. The hot liquid passes through the coils on the outside of the refrigerator and releases heat to the air outside in an isobaric compression process. The compressor, driven by an external source of energy, does work on the refrigerant during each cycle.

State the factors which control the wavelength of light emitted by an LED.

The colour of the light i.e. it's wavelength, emitted by an LED depends on the compound semiconductor material used and it's composition ( and doping levels. ) 

What is wattless current

The current that does not lead to power consumption is called wattless current. In the case of a purely inductive circuit or a purely capacitive circuit, average power consumed over a complete cycle is zero and hence the corresponding alternating current in the circuit is called wattless current.

hydraulic lift

A hydraulic lift is a machine consisting of two oil-filled cylinders hydraulically connected. It is used for lifting a heavy object by applying a small force on the oil which transmits the pressure.

What is a heat engine?

A heat engine is a device which takes a system through a repeated thermodynamic cycle that converts part of the heat supplied by a hot reservoir into work ( mechanical energy ) and releases the remaining part to a cold reservoir.At the end of every cycle, the system is returned to the initial state.

Compare resistance and reactance

Resistance is opposition to flow of charges (current) and appears in a DC Circuit as well as in an AC circuit. In a purely resistive circuit, current and voltage are always in phase. When reactance is not zero.there is nonzero phase difference between current and voltage. Resistance does not depend on the frequency of AC unless the frequency is very high.     Reactance depends on the frequency of AC. In case of an inductor, reactance increases linearly with frequency. In case of a capacitor, reactance decreases as frequency of AC increases; it is inversely proportional to frequency. Resistance gives rise to production of joule heat in a component.ln a circuit with pure reactance, there is no production of heat.

write a short note on biological importance of water

Water is absolutely necessary of life. What is the major constituent of protoplasm. It provides aqueous medium for various metabolic reactions that take place in plant. It is raw material for photosynthesis. It helps in maintaining the turgidity of cells. It is excellent solvent for various organic materials. It is transporting medium for dissolved minerals. It is thermal buffer.

what is colostrum and what is it's role.?

Colostrum is the first milk which is sticky and yellowish secreted by the mammary glands soon after the parturition. Being high protein in its content, it nourishes the newly born child. The antibodies present in it helps in developing resistance for the newborn baby at a time when it's own immune response is not fully developed.

Leydig's cells & Sertoli cells

Leydig's Cells Leydig's Cells are present in testis which secrete testosterone or androgen which is male sex hormone. Sertoli Cells Sertoli Cells provide nourishment and surface to the sperm bundles during their development.

auxin apical dominance

Auxin -Apical dominance Cytokinin- promotion of growth of lateral buds Gibberellins-Bolting rosette plants Abscission acid  - stimulate flowering in SDP