Mention the substances that exit from the tubules in order to maintain a concetration gradient in the medullary interstitium.

The mass per unit volume of a substance is called density.(density=mass/volume). Arrange the following in order of increasing density -air, exhaust from chimneys, honey water, chalk, cotten and iron,

Read the following passage and answer the questions. Adsorption is surface phenomenon and its differ from absorption, Which occurs throughout the body of the substance which abosorbs. In physisorption, the attractive forces are mainly van der waals forces while in chemisorption actual bonding occuars between the particles of absorbent and absorbate. Generelly, easily liquifying gases are absorved more easily on the surface of a solid as compared to the gases which are liquified with difficulty. Adsorption increases with the increase in pressure and decreases as the temparature is increased. Arrange the following gases in the decreasing order of the ease with which they are adsorbed on charcoal. H_2 , CH_4 , CO_2 and NH_3

Figure 3.33 shows a potentiometer with a cell of 2.0 V and internal resistance 0.40 Omega maintaining a potential drop across the resistor wire AB. A standard cell which maintains a constant emf of 1.02 V (for very moderate currents upto a few mA) gives a balance point at 67.3 cm length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600 k Omega is put in series with it, which is shorted close to the balance point. The standard cell is then replaced by a cell of unknown emf epsilon and the balance point found similarly, turns out to be at 82.3 cm length of the wire. Would the circuit work well for determining an extremely small emf, say of the order of a few mV (such as the typical emf of a thermo-couple)? If not, how will you modify the circuit?: