M = molar mass of the helium gas = 4.0 g/mol
m = mass of the gas given = 18.0 g
n = number of moles of the gas
number of moles of the gas is given as
n = m/M
n = 18.0/4.0
n = 4.5 moles
P = pressure = 2.00 atm = 2.00 x 101325 Pa = 202650 Pa
V = Volume of balloon = ?
T = temperature = 297 K
R = universal gas constant = 8.314
Using the ideal gas equation
P V = n R T
(202650) V = (4.5) (8.314) (297)
V = 0.055 m³
Average speed of the car is defined as the ratio of total distance and total time
So here we will have
now we know that
time = 5 h
now from above equation we will have
so the average speed will be 90 km/h
Answer:
Explanation:
Given
Four Point charges are Placed at the corner of a square with side length a
Length of diagonal 
Distance of charge from center 
Potential at the center due to four charges is given by
as all the four charges are equal and placed symmetrical about center
Work done required to bring a fifth charge q from infinity to the center of the square
Answer:
a) ∆U < 0 and ∆K > 0
Explanation:
The initial kinetic energy is zero since the objects are at rest
KE₁ = 0
The final kinetic energy is positive which means
KE₂ > 0
Therefore, the change is kinetic energy is positive
∆KE > 0
The change in gravitational potential energy is negative since the masses are unequal
Lets suppose mass of 1st object is m₁ and mass of 2nd m₂ and m₂ > m₁
∆U = m₁gh (positive)
∆U = m₂gh (negative)
Since m₂ > m₁ Total change in gravitational potential energy will be negative
∆U < 0
Therefore, the correct option is (a)
∆U < 0 and ∆K > 0
