Answer:
There are atoms when the sample of cerium is 20 seconds old.
Explanation:
The decay of isotopes is modelled after the following exponential expression:
(1)
Where:
- Initial number of atoms, dimensionless.
- Current number of atoms, dimensionless.
- Time, measured in seconds.
- Half-time, measured in seconds.
Now we clear the half-time within (1):
If we know that , and , then the half-life of the isotope is:
And the decay equation for the sample is described by:
Lastly, if we get that , then the activity of the sample of cerium is:
There are atoms when the sample of cerium is 20 seconds old.
Answer:
3924 N
5124 N
4004 N
2884 N
4004 N
Explanation:
m = Mass of elevator = 400 kg
g = Acceleration due to gravity = 9.81 m/s²
a = Acceleration
f = Friction force = 80 N
When the elevator is stationary only the acceleration due to gravity will be acting on it
Tension
The tension is 3924 N
The balanced force equation would be
The tension is 5124 N
When velocity is constant acceleration is zero
The tension is 4004 N
The tension would be 2884 N
When velocity is constant acceleration is zero
The tension is 4004 N
The conservation of the mass of fluid through two sections (be they A1 and A2) of a conduit (pipe) or current tube establishes that the mass that enters is equal to the mass that exits. Mathematically the input flow must be the same as the output flow,
The definition of flow is given by
Where
V = Velocity
A = Area
The units of the flow of flow are cubic meters per second, that is to say that if there is a continuity, the volume of input must be the same as that of output, what changes if the sections are modified are the proportions of speed.
In this way
(5 bulbs) x (25 watt/bulb) x (6 hour/day) x (30 day/month) =
(5 x 25 x 6 x 30) watt-hour/month =
22,500 watt-hour/month .
The most common unit of electrical energy used for billing purposes
is the 'kilowatt-hour' = 1,000 watt-hours .
22,500 watt-hour/month = <em>22.5 kWh/month</em>.
(22.5 kWh/month) x (1.50 Rs/kWh) = <em>33.75 Rs / month
</em>
Answer: The correct answer is option (D).
Explanation:
Voltmeter is a device which measures the the voltage applied across the circuit. It is an electrical instrument used to measure the electric potential between the two points in an electric circuit.
Where as:
A switch is the device which used to connect or disconnect the circuit.
Resistor is a device which opposes the flow of current is an electric circuit.
An ammeter the is an electrical device which measures the amount of current in flowing in amperes in an electrical circuit
Hence,the correct answer is option (D).