Physic Problems

Introduction to physics:

Physics is a natural science that involves the study of matter and its motion through spacetime, as well as all applicable concepts, such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the world and universe behave. (Source: From Wikipedia).

Some of the important topics in physics are electricity, magnetic field, reflection and refraction.Now, we are going to see some of the problems physics. Having problem with Ferromagnetism Definition keep reading my upcoming posts, i will try to help you.

Pysics Problems:

Example problem 1:

How much current will an electric heater connected to a 220v line draw if its resistance is 45 ohms?

Given:

Resistance R= 45 ohms

Voltage V= 220v

Current I=?

Solution:

According to ohm’s law, I=V/R

Therefore, I=220/45=4.89A

Example problem 2:

A lamp of 100 watts glows for 2 hours daily. Calculate the energy consumed in 30 days.

Given:

P=100 watt=0.1 kilowatt

T=2 hours

W=?

Solution:

The energy spent in 1 day,

W=p*t

W=0.1kW*2hours

W== 0.2 kWh

The energy spent in 30 days,

W= 0.2*30

W=60kWh

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Few more Physics Problems:
Example problem 3:

If an electrical lamp lights for 2 hours drawing current of 0.4 A, calculate the amount of charge that passed through the lamp?

Given:

Current I=0.4 A

t=2hours

t=2*60*60=7200 seconds

Q=?

Solution:

Amount of charge Q= I*t

Q=0.4*7200=2.88*10^3 C.

Example problem 4:

Calculate the net resistance of resistance 10 ohms, 5 ohms and 15 ohms connected in parallel.

Given:

R1=10 ohms

R2=5 ohms

R3= 15 ohms

Solution:

The net resistance R is given as,

(1/R) = (1/R1) + (1/R2) + (1/R3)

Putting the values, we get

(1/R) = (1/R1) + (1/R2) + (1/R3)

(1/R)= (1/10) + (1/5) + (1/15)

1/R = 0.1+0.2+0.066=0.366

Therefore, R=2.73 ohms

Example problem 5:

A lamp of resistance 20 ohm is joined with a battery of 12v. Find the value of another resistance to be connected in series with the lamp in order to get the current of 0.5 A.

Given:

Voltage V=12v

Current I=0.5A

Resistance of the lamp R1=20 ohms

Another resistance R2=?

Solution:

The total resistance of the circuit

R=R1+R2

Using ohm’s law,

V=IR

R=V / I = 12 / 0.5 24 ohms

But R=R1+R2

R2= R-R1=24-20=4 ohm.