Answer:
A 1.0 min
Explanation:
The half-life of a radioisotope is defined as the time it takes for the mass of the isotope to halve compared to the initial value.
From the graph in the problem, we see that the initial mass of the isotope at time t=0 is

The half-life of the isotope is the time it takes for half the mass of the sample to decay, so it is the time t at which the mass will be halved:

We see that this occurs at t = 1.0 min, so the half-life of the isotope is exactly 1.0 min.
Answer:

Explanation:
Given that,
The current flowing in the circuit, I = 3 A
The power of the battery, P = 25 W
We need to find the resistance of the battery. We know that the power of the battery is given by the formula as follows :

Put all the values to find R.

So, the resistance is equal to
.
The answer is Air Resistance
Answer:
R= 5.4 ohms
Explanation:
Given that
V= 9 V
Power ,P= 15 W
Lets take resistor resistance = R
We know that Power given as

V=Voltage
P=Power
R=Resistance

Now by putting the all the values in the above equation

R= 5.4 ohms
Therefore the resistance of the resister will be 5.4 ohms.