Answer:
LED run before the batteries are depleted is 3.87 hours
Explanation:
given data
battery = 4 AA
battery is rated = 1.2V, 2550 mAh
power = 3 W
efficient = 95%
to find out
How long will the LED run before the batteries are depleted
solution
we consider here power delivered by battery is = x
so power = x × efficient
3 = x 95%
x = 3.15 W
and
voltage by 4 battery is = 4 × 1.2 = 4.8 V
so current will be = 
current = 
current = 0.6577 A
so total discharge hours = 
total discharge hours = 
time = 3.87 hours
so LED run before the batteries are depleted is 3.87 hours
Explanation:
The given data is as follows.
Mass of evaporating dish = 3.375 g
Total mass = Mass of solid sample + evaporating dish
That is, Mass of solid sample + evaporating dish = 26.719 g
Therefore, we will calculate the mass of solid sample as follows.
Mass of solid sample = (Mass of solid sample + evaporating dish) - mass of evaporating dish
= 26.719 g – 3.375 g
= 23.344 g
Thus, we can conclude that mass of his solid sample must be 23.344 g.
Answer:
the train stopped for 3 seconds
Explanation: