17 , d . because a force is being applied but it is not moving .
19 . is c .
20 .b .
21 . d .
31 . d .
Answer:
The new radius is three times the initial radius
Explanation:
The magnetic force is given by the equation
F = q v x B
Where the blacks indicate vectors, q is the electric charge, v the velocity of the particle and B the magnetic field. The scalar magnitude of this force is
F = q v B sin θ
Where θ is the angle between the velocity and the magnetic field.
As the force is perpendicular to the velocity, the particle describes a circular motion, using Newton's second law we can find the acceleration that is centripetal.
F = ma
a = v² / r
q v B = mv² / r
R = mv / qB
Let's calculate for the new speed (v₂ = 3v)
R₂ = (m / qB) 3v
R₂ = 3 R
R₂ / R = 3
The new radius is three times the initial radius
Answer:
Volume increases
Explanation:
The balloon when filled at sea level being comparatively close to the center of the earth will have higher pressure due to the influence of gravity and when this balloon is taken to the top of the mountain being away from the center of earth, it will experience a lesser pressure due to low gravity where the amount of force exerted by the air on the object is lesser as compared to to that at the sea level.
Therefore, there will be an increase in volume of the balloon as there is expansion of air on the inside of the balloon as a result of low pressure.
There is not much effect of temperature at both the sea level and the mountain top as the temperature does not impart any energy to the air molecules so as to decrease the volume.
Therefore,there is an increase in the volume of the balloon at the top of the mountain.
Percentage change in volume is given by:

Answer: B. CO
Explanation:
Diatomic molecules are those that are formed by two atoms of the same chemical element (homonuclear diatomic molecule) or different chemical element (heteronuclear diatomic molecule).
In this sense, oxygen is a homonuclear diatomic molecule because it is formed by two atoms of the same element (
) and Carbon monoxide (
) is heteronuclear diatomic molecule.
Sodium Chloride
is not a diatomic molecule because is a product of ionization, but it can be diatomic in its gas phase with a polar covalent bond.