The answer is:
B)They are in the same group because they have similar chemical properties, but they are in different periods because they have very different atomic numbers.
The explanation:
The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties.
A period is a horizontal row of elements on the periodic table. For example, the elements sodium ( Na ) and magnesium ( Mg ) are both in period 3. The elements astatine ( At ) and radon ( Rn ) are both in period 6.
Answer:
T = 60 s
Explanation:
There are 6 poles on the track which are equally spaced
so the angular separation between the poles is given as


so the angular speed of the train is given as


now we have time period of the train given as



Answer:
35 m/s down
Explanation:
The horizontal speed of the package is 70 m/s. So the time needed to reach the hikers is:
1000 m / (70 m/s) = 14.28 s
Taking down to be positive, the initial velocity needed is:
Δy = v₀ t + ½ at²
1500 m = v₀ (14.28 s) + ½ (9.8 m/s²) (14.28 s)²
v₀ = 35 m/s
The package must be launched down with an initial velocity of 35 m/s.
Answer:
E = k*Q₁/R₁² V/m
V = k*Q₁/R₁ Volt
Explanation:
Given:
- Charge distributed on the sphere is Q₁
- The radius of sphere is R₁
- The electric potential at infinity is 0
Find:
What is the electric field at the surface of the sphere?E.
What is the electric potential at the surface of the sphere?V
Solution:
- The 3 dimensional space around a charge(source) in which its effects is felt is known in the electric field.
- The strength at any point inside the electric field is defined by the force experienced by a unit positive charge placed at that point.
- If a unit positive charge is placed at the surface it experiences a force according to the Coulomb law is given by
F = k*Q₁/R₁²
- Then the electric field at that point is
E = F/1
E = k*Q₁/R₁² V/m
- The electric potential at a point is defined as the amount of work done in moving a unit positive charge from infinity to that point against electric forces.
- Thus, the electric potential at the surface of the sphere of radius R₁ and charge distribution Q₁ is given by the relation
V = k*Q₁/R₁ Volt