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Browse complete papersElectric potential at a point is defined as the work done in bringing a unit positive charge from infinity to that point ________.
Without changing kinetic energy
With infinite acceleration always
Only in magnetic fields
Along a circular closed path
Correct answer
Without changing kinetic energy
Plaster of Paris is prepared by heating which of the following substances?
Calcium carbonate
Gypsum
Sodium chloride
Calcium hydroxide
Correct answer
Calcium carbonate
What determines the reactivity of elements in chemical reactions?
Reactivity independent of electron transfer in reactions
Reactivity depends on ease of electron loss or gain
Reactivity depends only on nuclear properties of atoms
Reactivity remains constant for all chemical elements
Correct answer
Reactivity independent of electron transfer in reactions
A cylinder fitted with a frictionless movable piston contains 2 moles of an ideal gas at 27°C and a volume of 10 L. The gas is heated to 127°C while maintaining constant pressure. What will be the final volume of the gas?
13.3 L
10.8 L
12.0 L
15.0 L
Correct answer
13.3 L
For an sp3 molecule with one lone pair, how and why does the bond angle change compared to the ideal tetrahedral angle?
The bond angle will decrease due to lone pair-bond pair repulsion
The bond angle will decrease due to increased nucleus attraction
The bond angle will increase due to electron sharing
The bond angle will remain unchanged due to stable geometry
Correct answer
The bond angle will decrease due to lone pair-bond pair repulsion
Cathode rays observed in discharge tubes are best described as:
Streams of electrons moving from cathode toward anode
Streams of photons emitted from heated metal electrodes
Streams of neutrons moving randomly inside the tube
Streams of protons moving from anode toward cathode
Correct answer
Streams of electrons moving from cathode toward anode
A sealed container holds equal masses of hydrogen and oxygen at the same temperature. Using the kinetic interpretation of temperature, what can be concluded about the average kinetic energies and speeds of the two types of gas molecules?
Both gases possess matching mean kinetic energies, but heavier oxygen molecules maintain higher average velocities.
Hydrogen molecules possess greater mean kinetic energies but simultaneously maintain matching average velocities.
Both gases possess matching mean kinetic energies, but lighter hydrogen molecules maintain higher average velocities.
Hydrogen molecules possess greater mean kinetic energies and simultaneously maintain higher average velocities.
Correct answer
Both gases possess matching mean kinetic energies, but heavier oxygen molecules maintain higher average velocities.
The spectral lines in a hydrogen series become closer together because the energy levels at higher n values __________.
Become closer together
Disappear completely
Remain equally spaced
Become farther apart
Correct answer
Become closer together
Which of the following statements correctly describe magnetic field lines around a bar magnet?
Outside the magnet, field lines go from North to South.
Inside the magnet, field lines go from North to South.
Magnetic field lines always form closed loops.
Magnetic field lines are discontinuous at the poles.
1, 2, 3 and 4
2 and 3 only
1 and 3 only
1, 2 and 4 only
Correct answer
1, 2, 3 and 4
Why is the net magnetic flux through any closed surface always zero?
Magnetic field lines are straight
Magnetic field is weak
Magnetic monopoles do not exist
Electric charges cancel magnetic field
Correct answer
Magnetic field lines are straight