S orbital.
Group 1 elements have a general configuration 
, where n represents the highest occupied Principal Energy Level. For example, Lithium has the valence configuration 
whereas Cesium has 
. Both of them belong to Group 1 of Periodic Table.
Group 2 elements have a general configuration of 
. For example, Magnesium has 
as its outer shell configuration while Strontium has the same as 
.
We see that in both the cases, the outermost S orbital is being filled.
If the period of a satellite is T=24 h = 86400 s that means it is in geostationary orbit around Earth. That means that the force of gravity Fg and the centripetal force Fcp are equal:
Fg=Fcp
m*g=m*(v²/R),
where m is mass, v is the velocity of the satelite and R is the height of the satellite and g=G*(M/r²), where G=6.67*10^-11 m³ kg⁻¹ s⁻², M is the mass of the Earth and r is the distance from the satellite.
Masses cancel out and we have:
G*(M/r²)=v²/R, R=r so:
G*(M/r)=v²
r=G*(M/v²), since v=ωr it means v²=ω²r² and we plug it in,
r=G*(M/ω²r²),
r³=G*(M/ω²), ω=2π/T, it means ω²=4π²/T² and we plug that in:
r³=G*(M/(4π²/T²)), and finally we take the third root to get r:
r=∛{(G*M*T²)/(4π²)}=4.226*10^7 m= 42 260 km which is the height of a geostationary satellite.
Heat equation, Q = m.c.Δt
Here, c represents " the specific heat of the substance "
Hope this helps!
Choice-A is the correct one. It doesn't say it, but it means he'll see the ball reach the catcher's mitt first BEFORE HE HEARS IT slap the mitt.
In the beginning, the melting stage they call it.
