Answer:
A. Atoms are the smallest unit of an element.
Explanation:
The correct statement from the given choices is that atoms are the smallest unit of an element.
Atoms are the smallest particles that takes part in chemical reactions and they are made up of protons, neutrons and electrons.
- Elements are distinct substances that cannot be split up into simpler substances.
- They are made up of only one kind of atoms.
- Elements are not changed into atoms by chemical reactions.
- In chemical reactions, atoms simply recombine.
Answer:
3.4 x 10^-4 T
Explanation:
A = 1.5 x 10^-3 m^2
N = 50
R = 180 ohm
q = 9.3 x 106-5 c
Let B be the magnetic field.
Initially the normal of coil is parallel to the magnetic field so the magnetic flux is maximum and then it is rotated by 90 degree, it means the normal of the coil makes an angle 90 degree with the magnetic field so the flux is zero .
Let e be the induced emf and i be the induced current
e = rate of change of magnetic flux
e = dФ / dt
i / R = B x A / t
i x t / ( A x R) = B
B = q / ( A x R)
B = (9.3 x 10^-5) / (1.5 x 10^-3 x 180) = 3.4 x 10^-4 T
Time = Distance / speed
Time = 2.5 km / 23 km/h
= 0.1087 hours 1 hour = 60 minutes
= 0.1087 * 60 minutes
= 6.522 minutes.
Answer:
5 ) The mass, 6) with lubrication and using surfaces that are not rough
Explanation:
5) If two bodies are held regardless of their densities and can be combined by some chemical or physical process, the only physical property to be modified will be the mass of the resulting body.
8)
Friction depends on the contact between two surfaces and when a body has a relative motion with respect to a contact surface. In order to reduce friction the contact surface must be lubricated, also the friction depends on the coefficient of friction between surfaces and the normal force exerted by the surface parallel to the area of contact with the body. Mathematically it can be expressed with the following equation.
![F_{f} = u*N\\where:\\u = friction coefficient\\N = normal force [Newtons]\\F_{f}= friction force [Newtons]](https://tex.z-dn.net/?f=F_%7Bf%7D%20%3D%20u%2AN%5C%5Cwhere%3A%5C%5Cu%20%3D%20friction%20coefficient%5C%5CN%20%3D%20normal%20force%20%5BNewtons%5D%5C%5CF_%7Bf%7D%3D%20friction%20force%20%5BNewtons%5D)
