In order to remove water from a flooded basement, two pumps, each rated at 45 gallons per minute, are used. after half an hour, the one pump burns out, and the second pump finishes removing the water half an hour later. how many gallons of water were removed from the basement?

4050 gallons

Explanation:

In first half and hour both pumps are working property . There for it give, 45

gallons per minute . Half and hour is equal to 30 minutes.After one pump was broken only one pump is working 30 minutes .

For 1st 30 minutes ,( 2 pumps are working )

Gallons = 45 * 30 *2 = 2700 gallons

2nd 30 minutes ( 1 pump is working )

Gallons = 45*30*1 = 1350 gallons

Total gallons = 2700+1350

= 4050 gallons

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.