Answer
t = 367.77 s = 6.13 min
Explanation:
According to the law of conservation of energy:

where,
P = Electric Power of Heater = 300 W
t = time required = ?
m_g = mass of glass = 300 g = 0.3 kg
m_w = mass of water = 250 g = 0.25 kg
C_g = speicific heat of glass = 840 J/kg.°C
C_w = specific heatof water = 4184 J/kg.°C
ΔT_g = ΔT_w = Change in Temperature of Glass and water = 100°C - 15°C
ΔT_g = ΔT_w = 85°C
Therefore,

<u>t = 367.77 s = 6.13 min</u>
The Green work gymno means Naked
Answer:
4 (D): twice the voltage, and the same current will flow through each.
Explanation:
When we have batteries in series in a circuit, the equivalent voltage will be the sum of their voltages, and the current flowing through then will be the same.
These batteries are identical, so they have the same voltage, therefore when they are put in series, the equivalent voltage will be twice the voltage of one battery.
So the correct option is 4 (D): twice the voltage, and the same current will flow through each.