Answer:
Explanation:
Check attachment for solution
Answer:
Torque decreases .
Explanation:
The tape is pulled at constant speed , speed v is constant , so there is
v = ω r where ω is angular speed and r is radius , As radius decreases , angular speed ω increases , So there is angular acceleration .
Let it be α . Let I be moment of inertia of reel .
Reel is in the form of disc
I = 1/2 m r²
I x α = torque
1/2 m r² x α = torque
As the reel is untapped , its mass decreases , r also decreases , so torques also decreases .
Answer:
Gallium
Explanation:
Gallium is one such element used as a do/pant in a p-type semiconductor.
A do/pant is an impurity added to a semi-conductor used to alter its properties. Semi-conductors have a wide range of applications. They will conduct heat and electricity only under certain conditions. This property is highly desirable and find a wide application in electronics.
For p-type conductors, they are best do/ped with elements with 3 valence electrons. These are group 3 elements. From the choices, only gallium belongs to this group.
Other elements given are good do/pants for n-type semiconductors. They have 5 valence electrons.
Answer:
61.85 ohm
Explanation:
L = 12 m H = 12 x 10^-3 H, C = 15 x 10^-6 F, Vrms = 110 V, R = 45 ohm
Let ω0 be the resonant frequency.
ω0 = 2357 rad/s
ω = 2 x 2357 = 4714 rad/s
XL = ω L = 4714 x 12 x 10^-3 = 56.57 ohm
Xc = 1 / ω C = 1 / (4714 x 15 x 10^-6) = 14.14 ohm
Impedance, Z = 
Z = \sqrt{45^{2}+\left ( 56.57-14.14 )^{2}} = 61.85 ohm
Thus, the impedance at double the resonant frequency is 61.85 ohm.
