Answer:
let me check the answer for you
Answer:C
Explanation: I studied, and C is correct
The force of earth's gravitational field is always directed downwards (towards the center of the earth. When the ball is thrown up, it is going against the earth's gravitational field and so, the earth's gravitational force pulls it back down, accelerating it downwards.
Answer:
False
Explanation:
As we know that, the Balmer series gives the n values as,
.
![[tex]n_{f}=3,4,5,.....\infty](https://tex.z-dn.net/?f=%5Btex%5Dn_%7Bf%7D%3D3%2C4%2C5%2C.....%5Cinfty)
.
Now the value of wavelength can be calculated as,
.
Here, 
.
And 
.
Now,
.
Therefore,
Therefore, the wavelength of Balmer series lies in visible region which is 547 nm.
Answer:
D. 2.8 × 10⁹ N
Explanation:
The force between two charges is directly proportional to the amount of charges at the two points and inversely proportional to the square of distance between the two points.
Fe= k Q₁Q₂/r²
Q₁= -0.0045 C
Q₂= -0.0025 C
r= 0.0060 m
k= 9.00 × 10 ⁹ Nm²/C²
Fe= (9.00 × 10 ⁹ Nm²/C²×-0.0045 C×-0.0025 C)/0.0060²
=2.8 × 10⁹ N
