Answer:
Explanation:
F = 2.12 x 10⁻²⁶ / x²
Work done by electric field of nucleus
W = ∫ Fdx
= ∫2.12 x 10⁻²⁶ / x² dx
= 2.12 x 10⁻²⁶ ( - 1 / x )
= - 2.12 x 10⁻²⁶ ( 1/5 - 1 / 8 x 10⁻¹⁰ )
= - .265 x 10⁻¹⁶ J
1/ 2 x mv² = .5 x 1.67 x 10⁻²⁷ x 9 x 10¹⁰ - .265 x 10⁻¹⁶
= 7.515 x 10⁻¹⁷ - .265 x 10⁻¹⁶
=( .7515 - .265 )x 10⁻¹⁶
= .4865 x 10⁻¹⁶
.5 x 1.67 x 10⁻²⁷ x v² = .4865 x 10⁻¹⁶
v² = .5826 x 10¹¹
v² = 5.826 x 10¹⁰
v = 2.41 x 10⁵ m /s
b )
Let r be the closest distance
Potential at this point
2.12 x 10⁻²⁶ ( 1 / r )
Kinetic energy
= 0
Total energy = 2.12 x 10⁻²⁶ ( 1 / r )
Total energy at 5 m
= .5 x 1.67 x 10⁻²⁷ x 9 x 10¹⁰ + 0 ( potential energy at 5 m will be negligible as compared with that near the center )
= 7.515 x 10⁻¹⁷ J
So ,
2.12 x 10⁻²⁶ ( 1 / r ) = 7.515 x 10⁻¹⁷
r = 2.12 x 10⁻²⁶ / 7.515 x 10⁻¹⁷
= .282 x 10⁻⁹
= 2.82 x 10⁻¹⁰ m
c ) As electric field is conservative , no dissipation of energy takes place . Hence its speed at 5m on returning back to this point will be same as
3.00 x 10⁵ m /s
Answer: precise
Explanation:
Three different people weight a standard mass of 2.00 g on the same balance. Each person obtains a reading of 2.32 g for the mass of the standard. These results imply that the balance that was used is precise.
Precision can be defined as the closeness of measured values to each other, for a measuring equipment it is the closeness of the values of readings obtained at different times to each other. It does not necessarily means the measurements are accurate(closeness to the actual value). Therefore, in the case above where three different people measured the same mass on the same balance, and each of them obtained the same value which is different from the standard value. We can say the balance used is precise because the three readings are the same.
Answer:
- a change in color
- the formation of a precipitate
- the formation of bubbles
Explanation:
In a chemical reaction, there is always a rearrangement of atoms within the molecules of reactants to form new products. Such a change is different from changes in the physical form of molecules, e.g. shape.
Thus, according to this criteria, only three options are correct in the given question. A change in color is definitely an indication of chemical reaction because the emission of light before and after cannot be changed unless molecules are rearranged to form a new chemical. Likewise, precipitates form when a reaction takes place between chemically dissolved molecules to form less or not dissolvable compounds. In the end, the configuration of bubbles also indicates that the reaction has taken place because new gases are being released.
On the other hand, change in shape is a physical change because the composition doesn't need to also been changed. An example is the ice formation from water. Same is the case with "change of clear liquid to cloudy" because the addition of non-reactive substances could change the nature of liquid to cloudy however the reaction doesn't need to have taken place.
Answer:
The correct option is: d. Fiber-optic
Explanation:
A fiber-optic cables or an optical-fiber cable is a cable that is composed of a bundle of optical fibers. These cables are used for transmitting information or digital signals over long distances.
Each optical fiber in an optical-fiber cable is individually coated with a protective plastic cover and contained in a protective tube. Therefore, an optical-fiber cable is not affected by any electromagnetic interference or radio frequency interference.
The re<span>sistance of the second wire is 16 R.
where R is the resistance of the first wire.
R = </span>ρ
where l = length of the wire
A = area of the wire
A =
where, r =
Thus, on finding the ratio of resistance of the two wires, we get,
here, R1 = R
l1 = 8m
l2 = 2m
A1=π
A1=π
we get. R2 = 16R
