Question 1

A repelling force must occur between two charged objects under which conditions?

Accepted Answer

Repelling forces occur between two charged objects when the charges are of like signs, according to Coulomb's law.

Question 2

If body M,with a positive charge,is used to charge body N by induction,what will be the nature of the charge left on the latter?

Accepted Answer

When body M, with a positive charge, is brought near body N, the electrons in body N are attracted towards body M, leaving behind a positive charge on body N. This process is known as induction. Therefore, the nature of charge left on body N must be opposite to the charge on body M, which in this case is negative. Thus, option B is the correct answer.

Question 3

Two point charges are 6 cm apart.They are moved to a new separation of 2 cm.By what factor does the resulting mutual force between them change?

Accepted Answer

The force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of their separation distance. Therefore, the new force will be:

(new force)/(old force) = (q1*q2/(2cm)^2)/(q1*q2/(6cm)^2) = (6cm/2cm)^2 = 9

So, the resulting mutual force between them changes by a factor of 9, which corresponds to answer choice D.

Question 4

I wish to use a positively charged rod to charge a ball by induction.Which statement is correct?

Accepted Answer

The answer of I wish to use a positively charged...

Question 5

A metallic object holds a charge of −5.3 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

Accepted Answer

The charge on the object is given as -5.3 × 10^-16 C. 
The electronic charge is given as 1.6 × 10^-19 C. 
To find the total number of electrons, we divide the charge on the object by the electronic charge:

(-5.3 × 10^-16 C) / (1.6 × 10^-19 C) = -3.3125 × 10^3

The result is negative because the object has a net negative charge. 
The absolute value of the answer gives the total number of electrons:

| -3.3125 × 10^3 | = 3.3 × 10^3

Therefore, the total number of electrons is 3.3 × 10^3, which is option C.

Question 6

If the size of the charge value is doubled for both of two point charges maintained at a constant separation,the mutual force between them will be changed by what factor?

Accepted Answer

The mutual force between two point charges is given by Coulomb's law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Mathematically, it can be written as:

F = k*q1*q2/r^2

where F is the force, k is Coulomb's constant, q1 and q2 are the magnitudes of the two charges, and r is the distance between them.

If the charge value of both point charges is doubled, the new force between them can be calculated as follows:

F' = k*(2q1)*(2q2)/r^2 = 4*(k*q1*q2)/r^2 = 4F

Therefore, the mutual force between the two charges is quadrupled or increased by a factor of 4. Hence, the correct answer is A) 4.

Question 7

Who was the first to determine the electron's charge?

Accepted Answer

Millikan was the first to determine the electron's charge through his famous oil drop experiment.

Question 8

Doug rubs a piece of fur on a hard rubber rod,giving the rod a negative charge.What happens?

Accepted Answer

When Doug rubbed a piece of fur on a hard rubber rod, electrons were transferred from the fur to the rod, giving the rod a negative charge. Therefore, option B - Electrons are added to the rod - is the correct choice. Option A, protons cannot be removed from the rod as they are bound in the atomic nucleus and are positively charged. Option C, the fur becomes charged positively due to losing electrons to the rod. Option D, the fur is left with an equal but opposite charge, so it becomes charged positively.

Question 9

About how many electrons are in 190 grams of water (H₂O)?

Accepted Answer

Water (H2O) has 10 electrons per molecule. The molar mass of water is 18 g/mol, so 190 g of water is approximately 10.56 moles. Avogadro's number (6.022 x 10^23) gives the number of molecules per mole, so 10.56 moles of water contains about 6.35 x 10^24 molecules. Multiplying by 10 electrons per molecule gives approximately 6.35 x 10^25 electrons, which is closest to 10^26.

Question 10

Which of the following best characterizes electrical insulators?

Accepted Answer

Electrical insulators are materials that do not allow electric charges to move freely through them, which means that charges on the surface don't move.

Question 11

When a glass rod is rubbed with silk,which of the following statements best describes what happens?

Accepted Answer

The answer of When a glass rod is rubbed with...

Question 12

How can a charged object attract an uncharged object made of non-conducting material?

Accepted Answer

When a charged object is brought near an uncharged non-conducting material, the charges in the material can become polarized, where the end closest to the charged object becomes oppositely charged, resulting in an attractive force. This can occur even though the material itself does not become charged.

Question 13

Which of the following best characterizes electrical conductors?

Accepted Answer

Electrical conductors allow electric charges to move freely through them. This is what makes them conductive. Mass density, tensile strength, and heat conductivity may vary among conductors, but the defining characteristic is the ability to conduct electricity.

Question 14

An uncharged conductor is supported by an insulating stand.I pass a positively charged rod near the left end of the conductor,but do not touch it.The right end of the conductor will be:

Accepted Answer

When a positively charged rod is brought near an uncharged conductor, the electrons in the conductor will move away from the rod towards the other end of the conductor. This creates a separation of charge, with the end opposite to the charged rod becoming positively charged. Therefore, the right end of the conductor will become positively charged.

Question 15

Two point charges,separated by 1.5 cm,have charge values of +2.0 and −4.0 µC,respectively.What is the value of the mutual force between them? (k_e = 8.99 × 10⁹ N⋅m²/C²)

Accepted Answer

The answer of Two point charges,separated by 1.5 cm,have charge...

Question 16

If body P,with a positive charge,is placed in contact with body Q (initially uncharged),what will be the nature of the charge left on Q?

Accepted Answer

When a positively charged body (P) is placed in contact with an uncharged body (Q), the electrons from body Q will move towards body P to neutralize it. This will leave the positive charge on body Q, making it positively charged as well. Therefore, the correct answer is (C) must be positive. The charge on body Q will be the same in magnitude as that on body P, but it will not be greater in magnitude. Hence, options (A) and (D) are incorrect. As the initial charge on body Q is zero, it cannot become negative. Therefore, option (B) is also incorrect.

Question 17

Of the following substances,which one contains the highest density of free electrons?

Accepted Answer

Iron is a metal and metals typically have a high density of free electrons. Hard rubber, amber, and glass are all insulators and do not have free electrons readily available for conduction.

Question 18

If the distance between two point charges is doubled,the mutual force between them will be changed by what factor?

Accepted Answer

According to the inverse square law of electrostatics, the force between two point charges is inversely proportional to the square of the distance between them. Therefore, if the distance is doubled, the force will be reduced to 1/4th of its original value. Hence, the answer is D, i.e., 1/4.

Question 19

When charging two objects by rubbing them together:

Accepted Answer

Rubbing two objects together creates a transfer of electrons between them, resulting in a charge imbalance that causes them to become charged. This process only works if the two objects are made of different materials, as the different atoms and molecules have different abilities to hold on to or give up electrons. If the objects were made of the same material, the electrons would move back and forth between them freely, resulting in no net charge imbalance.

Question 20

The constant k_e,which appears in Coulomb's law formula,is equivalent dimensionally to which of the following?

Accepted Answer

The constant $k$ in Coulomb's law, which is dimensionally equivalent to $N \cdot m^2 / C^2$, is represented in the question as $N \cdot m^{²} / C^{²}$, where the superscript notation $²$ likely indicates squared units, thus matching the dimensional formula for $k$.

Quiz 15: Electric Forces and Electric Fields

A repelling force must occur between two charged objects under which conditions?

If body M,with a positive charge,is used to charge body N by induction,what will be the nature of the charge left on the latter?

Two point charges are 6 cm apart.They are moved to a new separation of 2 cm.By what factor does the resulting mutual force between them change?

I wish to use a positively charged rod to charge a ball by induction.Which statement is correct?

A metallic object holds a charge of −5.3 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

If the size of the charge value is doubled for both of two point charges maintained at a constant separation,the mutual force between them will be changed by what factor?

Who was the first to determine the electron's charge?

Doug rubs a piece of fur on a hard rubber rod,giving the rod a negative charge.What happens?

About how many electrons are in 190 grams of water (H₂O) ?

Which of the following best characterizes electrical insulators?

When a glass rod is rubbed with silk,which of the following statements best describes what happens?

How can a charged object attract an uncharged object made of non-conducting material?

Which of the following best characterizes electrical conductors?

An uncharged conductor is supported by an insulating stand.I pass a positively charged rod near the left end of the conductor,but do not touch it.The right end of the conductor will be:

Two point charges,separated by 1.5 cm,have charge values of +2.0 and −4.0 µC,respectively.What is the value of the mutual force between them? (k_e = 8.99 × 10⁹ N⋅m²/C²)

If body P,with a positive charge,is placed in contact with body Q (initially uncharged) ,what will be the nature of the charge left on Q?

Of the following substances,which one contains the highest density of free electrons?

If the distance between two point charges is doubled,the mutual force between them will be changed by what factor?

When charging two objects by rubbing them together:

The constant k_e,which appears in Coulomb's law formula,is equivalent dimensionally to which of the following?

Quiz 15: Electric Forces and Electric Fields

A repelling force must occur between two charged objects under which conditions?

If body M,with a positive charge,is used to charge body N by induction,what will be the nature of the charge left on the latter?

Two point charges are 6 cm apart.They are moved to a new separation of 2 cm.By what factor does the resulting mutual force between them change?

I wish to use a positively charged rod to charge a ball by induction.Which statement is correct?

A metallic object holds a charge of −5.3 × 10−6 C.What total number of electrons does this represent? (e = 1.6 × 10−19 C is the magnitude of the electronic charge. )

If the size of the charge value is doubled for both of two point charges maintained at a constant separation,the mutual force between them will be changed by what factor?

Who was the first to determine the electron's charge?

Doug rubs a piece of fur on a hard rubber rod,giving the rod a negative charge.What happens?

About how many electrons are in 190 grams of water (H2O) ?

Which of the following best characterizes electrical insulators?

When a glass rod is rubbed with silk,which of the following statements best describes what happens?

How can a charged object attract an uncharged object made of non-conducting material?

Which of the following best characterizes electrical conductors?

An uncharged conductor is supported by an insulating stand.I pass a positively charged rod near the left end of the conductor,but do not touch it.The right end of the conductor will be:

Two point charges,separated by 1.5 cm,have charge values of +2.0 and −4.0 µC,respectively.What is the value of the mutual force between them? (ke = 8.99 × 109 N⋅m2/C2)

If body P,with a positive charge,is placed in contact with body Q (initially uncharged) ,what will be the nature of the charge left on Q?

Of the following substances,which one contains the highest density of free electrons?

If the distance between two point charges is doubled,the mutual force between them will be changed by what factor?

When charging two objects by rubbing them together:

The constant ke,which appears in Coulomb's law formula,is equivalent dimensionally to which of the following?

A metallic object holds a charge of −5.3 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

About how many electrons are in 190 grams of water (H₂O) ?

Two point charges,separated by 1.5 cm,have charge values of +2.0 and −4.0 µC,respectively.What is the value of the mutual force between them? (k_e = 8.99 × 10⁹ N⋅m²/C²)

The constant k_e,which appears in Coulomb's law formula,is equivalent dimensionally to which of the following?