Answer:
vi) Double the current in the wire, and double the number of turns in the 20-cm long solenoid
Explanation:
The magnetic field inside the solenoid and the current flowing in the coil of solenoid are related to each other by the following equation
B₀=μ₀nI₀
Where,
B₀ is the magnetic field in the middle of solenoid
n is the number of turns in the coil of solenoid
I₀ is the current flowing in the coil of solenoid
In the above equation, as μ₀ is a constant so the magnetic field will be directly proportional to the number of turns multiplied by the current. So, changing the radius of the coil or length of the coil will have no effect on the magnetic field.
As we have to increase the magnetic field by 4 times, we need to double the current as well as the number of turns as mentioned in the option vi.
S~ cientists publish their original research in scientific journals, which are fundamentally different from news magazines. The articles in scientific journals are not written by journalists – they are written by scientists. Scientific articles are not sensational stories intended to entertain the reader with an amazing discovery, nor are they news stories intended to summarize recent scientific events, nor even records of every successful and unsuccessful research venture. Instead, scientists write articles to describe their findings to the community in a transparent manner.
Answer:
cargo planes hold cargo so there hevier
Explanation:
Passengers in an aircraft are subject to the Normal and Gravity Force acting on them at a low 'orbit', so tiny that it can be many times compared to the same surface of the earth when speaking in general terms.
In a high orbit space vehicle or in the same space, said force decreases considerably or simply disappears, generating the sensation of weightlessness.
Remember that the Force of Gravity is given under the principle

Where,
G = Gravitational Universal constant
M = Mass of the planet
m = mass of the object
r = Distance from center of the planet
When the radius grows considerably the gravitational force begins to decrease.
9 × 10²¹ electrons flow through a cross section of the wire in one hour.
<h3>What is the relation between current and charge?</h3>
- Mathematically, current = charge / time
- In S.I. unit, Charge is written in Coulomb and time in second.
<h3>What is the amount of charge flown through a wire for one hour if it carries 0.4 A current?</h3>
- Charge= current × time
- Current= 0.4 A, time = 1 hour= 3600 s
- Charge= 0.4× 3600
= 1440 C
<h3>How many numbers of electrons present in 1440C of charge?</h3>
- One electron= 1.6 × 10^(-19) C
- So, 1440 C = 1440/1.6 × 10^(-19)
= 9 × 10²¹ electrons
Thus, we can conclude that the 9 × 10²¹ electrons flow through a cross section of the wire in one hour.
Learn more about current here:
brainly.com/question/25922783
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