A 4.9 A current is set up in a circuit for 5.4 min by a rechargeable battery with a 6.0 V emf. By how much is the chemical energy of the battery reduced?

E =9525.6 J        

Explanation:

Given that

Current ,I = 4.9 A

time ,t = 5.4 min

Voltage difference ,ΔV = 6 V

energy delivered by battery in time t is given as

E=V I t

where V is voltage, I is the current and t is the time.

now putting the values in above equation

E= 6 x 4.9 x 5.4 x 60  J   ( 1 min = 60 s , 5.4 min  = 5.4 x 60 s)

E =9525.6 J

Therefore the energy reduced will be 9525.6 J

this is poiselle's equation from fluid mechanic in physics. mech eng

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.