Answer:

Explanation:
To calculate the average velocity we must know the distance traveled and do
. The distance traveled is
, so we need to calculate the acceleration, which, since it's uniform, is
. Putting all together:

Answer:
The correct option is (A).
Explanation:
When the temperature of the hot solid object increases then the radiation which emits from it gets shifted to smaller wavelength or higher frequencies. The hot appears red color.
The total energy emitted of a hot solid object is directly proportional to the fourth power of the temperature of the black body.
For example, when we switch on the light bulb, initially the radiation of the bulb appears dimmer. Then, it will become brighter. Then, it will turn yellow and then it becomes even white.
The color of the light emitted by a hot solid object depends on the temperature of the object.
Therefore, the correct option is (A).
Answer:
Magnetic field, B = 0.004 mT
Explanation:
It is given that,
Charge, 
Mass of charge particle, 
Speed, 
Acceleration, 
We need to find the minimum magnetic field that would produce such an acceleration. So,

For minimum magnetic field,



B = 0.004 T
or
B = 4 mT
So, the magnetic field produce such an acceleration at 4 mT. Hence, this is the required solution.
Answer: No, The energy will remain the same
Explanation: Doubling the mass and leaving the amplitude unchanged won't have any effect on the total energy of the system.
At maximum displacement, E=0.5kA^2
Where E = total energy
K = spring constant
A = Amplitude
From the formula above : Total Energy is independent of mass,. Therefore, total energy won't be affected by Doubling the mass value of the object.
Also when the object is at a displacement 'x' from its equilibrium position.
E = Potential Energy(P.E) + Kinetic Energy(K.E)
P.E = 0.5kx^2
Where x = displacement from equilibrium position
E = Total Energy
K. E= E-0.5kx^2
From the relation above, total energy is independent of its mass and therefore has no effect on the total energy.