70 Questions
Which type of charge does a proton have?
Positive charge
What is the SI unit of charge?
Coulomb
Which type of charge does an electron have?
Negative charge
What happens when two charges of the same type (positive or negative) are brought close together?
The force between them is repulsive
What happens when two charges of different types (positive and negative) are brought close together?
The force between them is attractive
What is a conductor?
A material through which charge flows easily
What is an insulator?
A material that does not conduct electricity
What happens to electrons in a conductor?
They are able to hop from atom to atom
What is the simplest way to induce a charge on many common materials?
Rubbing unlike materials together
What is the charge of a neutron?
Neutral charge
Which object ends up with a net positive charge when two objects made of unlike materials are rubbed together?
The object made of the most electropositive material
What happens to the total charge when two objects made of unlike materials are rubbed together?
The total charge remains the same
What is polarization?
The separation of charge within an object
What are the three types of polarization?
Permanent, induced, and instantaneous
What is permanent polarization?
When one side of a molecule is more positive than the other
What is induced polarization?
When charges accumulate on the ends of a conductor
What happens to charges in a conductor during induced polarization?
Charges can move throughout the conductor
What happens to charges in an insulator during induced polarization?
Charges are bound to a particular location in the insulator
What is the net charge of an object that is polarized?
Zero
What is the name for molecules that have a permanent separation of charge within them?
Polar molecules
According to Coulomb's law, the force between two electric charges is directly proportional to the product of the charges and inversely proportional to their separation squared. Which equation represents Coulomb's law?
$F = k \frac{q_1 q_2}{r}$
What is the magnitude of the electric force between two charges of magnitude $q_1 = 2 \mu C$ and $q_2 = 3 \mu C$ separated by a distance of 2 meters?
$1.44 N$
If the charge $q_2$ in the previous question is negative, how would the direction of the electric force change?
It would become attractive
What is electrocardiography (ECG) used for?
Recording the electrical activity of the heart
What does an electrocardiogram (ECG) detect?
The electrical changes on the skin
What is the SI unit of charge?
Coulomb (C)
What is the net charge of an object that is polarized?
Zero
What happens to charges in a conductor during induced polarization?
Charges move freely within the conductor
What is the name for molecules that have a permanent separation of charge within them?
Polar molecules
What happens to electrons in a conductor?
Electrons move freely within the conductor
Which of the following is true about the electrical signal generated at the sinoatrial (SA node) of the heart?
It causes the contraction of the atria
What is the normal range of the pacemaking signal from the SA node in the heart?
Between 60 and 100 beats/min
What is the potential difference between the inside and outside of the cells of the outer membrane of the heart at the resting state?
Around 90 mV
What is the primary tool used for detecting abnormal heart rhythms?
Electrocardiogram (ECG) machines
What does the P wave on an electrocardiogram (ECG) represent?
Depolarization of the atria
What does the QRS complex on an electrocardiogram (ECG) represent?
Depolarization of the ventricles
What does the T wave on an electrocardiogram (ECG) represent?
Repolarization of the ventricles
What is the SI unit of capacitance?
Farad
What does the capacitance of a capacitor depend on?
The dielectric constant
What is the capacitance of 1 cm^2 of membrane that separates ions inside and outside a cell, with a dielectric constant of 8?
7.08 × 10^-7 F
Which of the following is true about the electrical signal in the heart?
It occurs at a rate between 60-100 beats/min
What is the potential difference between the inside and outside of the cells in the outer membrane of the heart at the resting state?
90 mV
What is the primary tool used for detecting abnormal heart rhythms?
Electrocardiogram (ECG)
What does the first bump (P wave) on an electrocardiogram (ECG) represent?
Depolarization of the atria
What does the last bump (T wave) on an electrocardiogram (ECG) represent?
Repolarization of the ventricles
What does the sharper feature in the middle (QRS complex) on an electrocardiogram (ECG) represent?
Depolarization of the ventricles
What is the formula for the capacitance of a capacitor?
$C = KA/d$
What factors affect the capacitance of a capacitor?
Dielectric constant, plate area, and distance between plates
What is the capacitance of 1 cm^2 of membrane with a dielectric constant of 8?
$0.708 \mu F$
What is the nerve cell's behavior similar to in terms of electrical conduction?
Capacitor
What is the resting membrane potential of a nerve cell?
-70 mV to -90 mV
During the active state of a nerve cell, what happens to the cell membrane permeability?
It increases suddenly
What is the approximate duration of an action potential in a nerve cell?
0.3ms
What is the primary mechanism responsible for the exchange of substances between the cell interior and the environment?
Diffusion
What is the role of the Na-K pump in a nerve cell?
It pumps sodium into the cell and potassium out of the cell
What is the range of the resting membrane potential of a nerve cell?
-70 mV to -90 mV
What is the polarity of the charge across the membrane during each stage of the nerve cell's electrical potential?
It keeps changing
What is the primary factor that determines the signal conduction velocity along a nerve axon?
Axon's diameter
What happens to the potential difference across the capacitors as one goes farther from the stimulus?
It decreases gradually
What is the approximate time required for the Na-K pump to restore the ions in a nerve cell?
50ms
What is the SI unit of electric current?
Ampere (A)
What is Ohm's law?
The resistance of a conductor is the potential difference between its ends divided by the current.
What is the opposition to the flow of electrical current through an object known as?
Resistance
What are materials that do not obey Ohm's law known as?
Non-Ohmic
What is the approximate capacitance of cell membranes?
10-2 Fm-2
What is the name for a two-molecule thick membrane formed from a phosphate group and a hydrocarbon chain?
Bilayer
What are materials called when the potential difference and the current are directly proportional?
Ohmic
What is the SI unit of electrical resistance?
Ohm (Ω)
What is the formula for electric resistance?
𝑹 = 𝑽 𝑰
What is the formula for finding the electric resistance?
𝑹 = 𝑽 𝑰
Test your knowledge of electric charge and its properties with this quiz. Learn about the different types of charges, their magnitudes, and how they interact with each other. Explore the concept of neutrality and the unit of electric charge.
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