A. Radio waves
Have the lowest frequencies
Answer:
B'=1.935 T
Explanation:
Given that
magnetic field ,B= 0.645 T
We know that magnetic filed in the solenoid is given as

I=Current
n=Number of turn per unit length
μ0 =magnetic permeability
Now when the current increased by 3 factors
I'=3 I
Then the magnetic filed


B'=3 B
That is why
B' = 3 x 0.645 T
B'=1.935 T
Therefore the new magnetic filed will be 1.935 T.
Answer:4
Explanation:
Given
Frequency of beats is 3 beats per second
Frequency of first tuning fork is 
Beat frequency is difference in the frequency of tuning forks i.e.
either
or 
so 
or

so there is not enough information given to decide.
Answer:
I = 24 A
Explanation:
This is Parallel Circuit and it is the first principle of parallel circuit that voltage will be equal in all components in the circuit
It includes 10 resistors Therefore the voltage across,
R1 = R2 = R3 = R4 = R5 = R6 = R7 = R8 = R9 = R10 = voltage in battery
<h2>
Ohm's Law</h2>
We will apply Ohm's Law to each resistor to find its current because we know the voltage across each resistor is 12 V and the resistance of each resistor is 5Ω
I (R1) = E (R1) / R1
I (R1) = 12v / 5Ω
I (R1) = 2.4 A
The value resistance E of all resistors are same therefore by applying the formula above the value of current in all resistors will be 2.4 A
The Total current in the circuit will be
I (total) = I (1) + I (2) + I (3) + I (4) + I (5) + I (6) + I (7) + I (8) + I (9) + I (10)
I (total) = 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4
I (total) = 24 A
Answer:
D. the linear velocity of the point of contact (relative to the inclined surface) is zero
Explanation:
The force of friction emerges only when there is relative velocity between two objects . In case of perfect rolling , there is no sliding so relative velocity between the surface and the point of contact is zero . In other words the velocity of point of contact becomes zero , even though , the whole body is in linear motion . It happens due point of contact having two velocities which are equal and opposite . One of the velocity is in forward direction and the other velocity which is due to rotation is in backward direction . So net velocity of point of contact becomes zero . Due to absence of sliding , displacement due to friction becomes zero . Hence work done by friction becomes zero.