Write True/False:
The hot air in the rooms rises up and flows out of ventilators. The fresh and cold air from outside flows into room from doors and windows.

During natural ventilation the _______ leaves from the ventilators. (cold air/warm air)

Plan an experiment and prepare a flow chart of the steps that you would follow to ensure that the seeds are formed only from the desired sets of pollen grains.Name the type of experiment that you carried out . ( b) Write the importance of such experimets.

In a room containing air, heat can go from one place to another

In a room containing air,, heat can go from one place to anther

On a winter day, the outside temperature is 0^(@)C and relative humidity 40%.The air from outside comes into a room and is heated to 20^(@)C. What is the relative humidity in the room? The saturated vapour pressure at 0^(@)C is 4.6mm of mercury and at 20^(@)C it is 18mm of mercury.

50 students sitting in the room of 5 xx 10 xx 3m^(3) dimensions. The air inside the room is at 27^(@)C and 1atm pressure. If each student loses 100 watt heat per second assuming the walls, ceiling floor, and all the material present inside the room is perfectly insulated as well as neglecting loss of air to the outside as the temperature is raised, how much rise in temperature will be noticed in 10min ? Given C_(P) = (7)/(2)R for air.

A block of metal is heated to a temperature much higher than the room temperature and allowed to cool in a room free from air currents. Which of the following curves correctly represents the rate of cooling

An air bubble in a water tank rises from the bottom to the top. Which of the following statements are true?

A spray gun is shown in the figure where a piston pushes air out of a nozzle. A thin tube of uniform cross section is connected to the nozzle. The other end of the tube is in a small liquid container. As the piston pushes air through the nozzle, the liquid from the container rises into the nozzle and is sprayed out. For the spray gun shown, the radii of the piston and the nozzle are 20mm and 1mm respectively. The upper end of the container is open to the atmosphere. If the density of air is rho_a , and that of the liquid rho_l , then for a given piston speed the rate (volume per unit time) at which the liquid is sprayed will be proportional to

a. Mark the follllowing statements as true offalse. i. A ball thrown vertically up takes moretime to go up than to come down. ii. If a ball starts fallig from the position of rest, then it travels a distance of 25 m during the third secons of tis fall. iii. A packet dropped from a rising balloon ferst moves upwards and then moves sownward as observed by a stationary observer on the ground. iv. In the absence of air resistance, all bodies fall on the surface of earth at the same rate. b. Fill in the blanks. i. When a body is thrown vertically upwards, at the highest point.........................(both belocity and accelenation are zero//only velocity is zero//ony acceleration is zero). ii. If air drag is not neglected, then which is greater: time of ascent or time of descent? iiii. A body is projected upward. Up to the maximum height time taken will be greater to travel...................... (first half//second half).