I am using 18 gauge nicrome wire having ohm of 17.3 , 220 volt. I want to use 10 gauge wire how to decide the length?
18 gauge corresponds to a diameter of 1.22 mm
Therefore radius r1= 1.22/2=0.61 mm=0.00061m
10 gauge means diameter is 3.25 mm
Radius r2 = 3.25/2=1.625mm=0.001625m
Sine the resistance needs to be the same, we can use the formula
As resistivity is same.
Substitute the values and you will get the answer.
A body weighs 30 kg on the surface of the earth how much would it weigh on the surface of a planet whose mass is 1/9 the mass of earth and radius is half of that of earth?
Weight on earth = 30 kg wt = 30 x g N
g on new planet, g’ = GM’/R’2=(4/9)g
Therefor weight on the new planet will be equal to 4/9 times its weight on earth
(Whereas the mass will be the same)
A group of UK Physicists claim that they have developed graphene bubbles which can change its curvature and hence its focal length and power by applying small voltages. If developed, this can be used in mobile cameras and other such devices. This would better imitate the functioning of Human Eye too.
More details available at http://physicsworld.com/cws/article/news/47250
A black of mass 1.5kg placed on a rough horizontal surface is pulled by a constant horizontal force of 1.2kg wt. the cofficient of friction between the block and the surface is 0.3. Find acceleration produced in terms of g.
(Posted by Ankur Srivastava)
Applied force, F=1.2 kg wt = 1.2g N (where g is the acceleration due to gravity)
Friction f=µmg=0.3 x 1.5 x g=0.45g N
The net force = ma
=> 1.5 x a = 1.2 g -0.45g=0.8 g
a = (0.8/1.5)g
if force F us given in terms of timeT and distance X f=AsinCT +BcosDX then the dimensions of A/B is equal to
Would shaking a bottle of chilled water, cause it to warm up, even slightly, due to some kind of friction?
Yes, This is due to friction (Viscous forces). The different layers of water resist relative motion and the work done in producing motion against the viscous force appears as heat.
CBSE has added some content for class XII. This includes mainly portions from “Combination of mirrors and lenses”
XII Class Supplementary Study Material