Answer: A) Transformer
Explanation: A Transformer is an apparatus, device or a component in a system that is used to convert high voltage into low voltage. It is used to either increase or decrease the voltage of an alternating current.
A transformer uses the basic principle of electro magnetic induction, having two or more coils, the voltage is changed from one coil to another but with thesame frequency as alternating current energy passes through them.
Answer:
5.16×10¹⁵ s
Explanation:
Considering the rotational motion of the Earth,
K.E. = ω² where, I = MR²
= MR²ω² ---------(1) where ω = angular velocity of Earth
To find ω,
ω = 2π/T where T = time period of Earth
= 2π/(60×60×24) = 7.27×10^-5 rad/s
Substituting the values in (1),
K.E. = 0.4×(6×10^24)×(6400000)²×(7.27×10^-5)²
= 5.16×10²⁹ J
To calculate possible time,
Time = Energy/ Power
= 5.16×10²⁹ / 10¹⁴
= 5.16×10¹⁵ s
Answer:
120 rpm
Explanation:
I1 = 105 kgm^2, I2 = 70 kgm^2
f1 = 80 rpm, f2 = ?
Let the angular speed be f2 when his arms are tucked.
If no external torque is applied, then the angular momentum remains constant.
L1 = L2
I1 w1 = I2 w2
I1 x 2 x 3.14 x f1 = I2 x 2 x 3.14 x f2
105 x 80 = 70 x f2
f2 = 120 rpm