Answer:

Explanation:
Given,
Magnetic field,B = 0.5 x 10⁻⁴ T
distance,r= 15 cm = 0.15 m
Current = ?
Using Ampere's law of magnetic field




Current in the wire is equal to 
To solve this problem we will apply the concept of frequency in a string from the nodes, the tension, the linear density and the length of the string, that is,

Here
n = Number of node
T = Tension
= Linear density
L = Length
Replacing the values in the frequency and value of n is one for fundamental overtone



Similarly plug in 2 for n for first overtone and determine the value of frequency



Similarly plug in 3 for n for first overtone and determine the value of frequency



Answer:
The change in the charge on the positve plate when the Teflon is inserted is +2.5 nC.
Explanation:
- It can be showed that the capacitance of a parallel-plate capacitor, can be expresssed as follows:

- Where ε, is the dielectric constant of the material that fills the space between plates.
- When this space is filled with air, ε= ε₀ = 8,85*10⁻¹² F/m.
- At the same time, the capacitance of a capacitor, by definition, is as follows:

- If we insert a Teflon slab, in such a way that fills completely the gap between the plates, all other parameters being equal, if ε = 2*ε₀, this means that C₂ = 2* C₁. = 50 pF
- As V₂=V₁ (due to the capacitor remains connected to the same battery) the charge must be the double, so Q₂ = 2* Q₁ = 5 nC.
- So, the change in the charge of the positive plate is +2.5 nC.
Answer:
Average mass of acar in the US (in kg) = 1440 kg
Explanation:
Average mass of a car in the US (in g) = 1.440 × 10⁶ g
Mass in kg:
