Each of two identical objects carries a net charge. the objects are made from conducting material. one of them is attracted to a positively charged ebonite rod, and the other is repelled by the rod. after the objects are touched together, it is found that they are each repelled by the rod. what can be concluded about the initial charges on the objects?
a) initially, both objects are positive, with both charges having the same magnitude.
b) initially both objects are negative, with both charges having the same magnitude.
c) initially one object is positive and one is negative, with the positive charge having a greater magnitude than the negative charge.
d) initially one object is positive and one is negative, with the negative charge having a greater magnitude than the positive charge.

It can be concluded that:

c) Initially one object is positive and one is negative, with the positive charge having a greater magnitude than the negative charge.

Explanation:

There is the property of charges by virtue of which like charges repel each other and unlike charges attract each other.

Given that,

Initially, one of the object is attracted to positively charged ebonite rod, therefore, it must have negative charge initially and the other is repelled by the rod, therefore, it must have positive charge initially.

When the two objects touched together, there is a redistribution of charges on them, such that, the net charge on both the objects distributes equally on both.

Since, it is found that they are each repelled by the rod after the objects touched each other, it means they both acquire positive charges.

Both the objects acquire positive charge implies that the net charge on the two objects, i.e., the sum of charges on the two objects, must be positive before they were touched which means that the object with the positive charge had charge greater in magnitude.

So the correct conclusion is:

c) Initially one object is positive and one is negative, with the positive charge having a greater magnitude than the negative charge.

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.