I’m pretty sure it’s, B. An Electric Motor. I apologize in advance if it’s incorrect.
Answer:
Only a backward force is acting, no forward force.
Explanation:
- Once released from the initial push, in absence of friction, the shopping cart would continue moving forward at a constant speed forever.
- As it would move at a constant speed, no net force would be acting on it.
- So, if it is gradually slowing, there must be a net force producing an acceleration in a direction opposite to the movement.
- This force is the kinetic friction force, and is the only force acting on the cart in the horizontal direction.
- As any friction force, opposes to the relative movement between the cart and the horizontal floor, which means that is directed backward.
- This is consistent with the direction of the acceleration of the cart.
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.
The correct answer would be D. A new experiment would be needed to be done in order to test the conclusions. In science there is no authority, data is the only thing that matters. So if we have two different conclusions from the same date the only solution is to perform more tests and more experiments to see what is correct.
