Field Theory Answers

hello experts

problem- A charge Q is placed at the centre of a square if electric field intensity due to the charge at the corners of the square is 'E' and the intensity at the mid point of the side of square is 'e'
then ratio of E/e will be?
NOTE- the Electric field mentioned here are different at both the points.

thanking you

Two equal point charges A and B are R distance apart. A third point charge placed on perpendicular bisector at a distance "d" from the centre will experience max electrostatic force when?????

An ideal gas undergoes a cycle of processes as shown in the p-V diagram gases . Which statement correctly describes the situation?
Click here to see exhibit
The internal energy of the gas increases over one complete cycle
Over the entire cycle, work is done by the gas.
The gas absorbs more heat than it releases heat over the whole cycle
The gas gives out more heat than it absorbs over the whole cycle.

2 A fixed mass of an ideal gas slowly releases 1500 J of heat and as a result contracts slowly, at a constant pressure of 2.0 x 104 Pa, from a volume of 0.050 m3 to 0.025 m3 . What is the effect on the internal energy of the gas?
It decreases by 2000 J.
It decreases by 1000 J.
It is unchanged.
It increases by 1000 J.

When the junctions of two dissimilar metals are maintained at different temperatures an electromotive force is is set up in the circuit of which these junctions are part. A pair of juntions of this kind and the effect are known respectively as
thermistor and Peltier effect
resistance thermometer and Joule effect
pyrometer and Joule effect
thermocouple and Seebeck effect

19 Which of the following is not an equation of state of a thermodynamic system?
Charles law
Ideal gas law
Van der Waals equation
Kirchoff's junction rule

20 Units for thermal conductivity
J/kg.K
J/mol.K
J.ohm/sec.K2
W/m.K

An engine absorbs 2000J of heat from a hot reservoir and expels 750J to a cold reservoir during each operating cycle. How much work is done during the cycle?
1250J
750J
2000J
350J

15 An engine absorbs 2000J of heat from a hot reservoir and expels 750J to a cold reservoir during each operating cycle. What is the efficiency of the engine?
50%
62.5%
74.2%
85.6%

16 Calculate the work done on the system when 1.00 mol of gas held behind a piston expands irreversibly from a volume of
1.00dm3
to a volume of
10.0dm3
against an external pressure of 1.00 bar.
-900 J
-1800 J
-1900 J
-60 J

17 A perfect gas expands reversibly at a constant temperature of 298 K so that its volume doubles. What is the change in the molar internal energy of the gas?
−0.125Jmol−1
0Jmol−1
983Jmol−1
1Jmol−1

Heat can be defined as------------------------
the change in temperature of a body
the flow of temperature from one body to another
energy that flows from place to place as a result of the difference in temperature between them
the measure of hotness or coolness of a body

11 Two bodies may be said to be in thermal equilibrium if
the bodies are thermally insulated from one another
the bodies are not in thermal equlibrium with another body
if one body loses heat to the other
if there not net flow of heat between the two bodies two bodies in thermal contact

12 Heat capacity has units as
J/kg.K
J/mol.K
J.ohm/sec.K2
W/m.K

13 An engine absorbs 2000J of heat from a hot reservoir and expels 750J to a cold reservoir during each operating cycle. What is the power output of the engine if each cycle lasts for 0.5 seconds?
750W
1750W
3000W
2500W

Airplane flight is best illustrated by
Boyle's law.
Bernoulli's principle.
Archimedes' principle.
Heat law

7 What is the buoyant force acting on a 10-ton ship floating in the ocean
10 tons
more than 10 tons
less than
depends on density of seawater

8 How much pressure do you experience, when you balance a 5 kg ball on the tip of your finger, which has an area of
1cm2?
490 kPa
4600 Pa
34 N
No answer

9 If you wish to warm 100 kg of water by
20oC
for your bath, how much energy is required? (Specific heat capacity of water is
1cal/goC
500 kcal
1000 kcal
2000 kcal.
3000 kcal

A fixed mass of an ideal gas slowly releases 1500 J of heat and as a result contracts slowly, at a constant pressure of 2.0 x 104 Pa, from a volume of 0.050 m3 to 0.025 m3 . What is the effect on the internal energy of the gas?
It decreases by 2000 J.
It decreases by 1000 J.
It is unchanged.
It increases by 1000 J.

3 A dam is thicker at the bottom than at the top because
surface tension exists only on the surface of liquids.
it looks better
water is denser at deeper levels.
water pressure is greater with increasing depth.

4 A completely submerged object always displaces its own
density of fluid.
weight of fluid.
volume of fluid.
all of these

5 When gas in a container is squeezed to half its volume, its density
quadruples.
halves.
doubles.
remains the same.

20 The temperature at which the tungsten filament of a 12 V and 36W lamp operates is
1730o
C. If the temperature coefficient of resistance of tungsten is
6×10−3
/K, find the resistance of the lamp at a room temperature of 20oC
10.00Ω
0.45Ω
0.39Ω
4.00Ω

Calculate the change in internal energy of 2kg of water at 90 degree celcius when it is changed to 330m3 of steam at 100oC. The whole process occurs at atmospheric pressure. The latent heat of vaporization of water is 226106 J/kg.
4.27 MJ
3.43 kJ
45.72 mJ
543.63 J

18 Tensile strain is mathematically expressed as:
Force/Area
initial length/extension
extension/initial lenght
Stress + initial lenght

19 A certain resistance thermometer at triple point of water has resistance of
152.0Ω
. What is the temperature of the system in degrees celcius when the resistance of the thermometer is
230.51Ω
?
414.2o
C
141.0o
C
253.2o
C
80.4o
C