Biophysics 2

Indicate how the energy of interaction between 2 dipoles depend on the distance r between them:

Indicate the formula describing the energy of Van der Waals interaction (A an B are constants >0 and r is the distance)

In the harmonic movement a particle is oscillating around the equlibrium point and y denotes the distance of particle from the equilibrium point. The harmonic force (F) inducing the harmonic movement is described as follows (k is the spring constant):

The ultrasonograph emits a pulse of ultrasound wave into the examined soft tissue at time t=0. The echo is detected at 0,1 ms. Assuming the sound velocity in the soft tissue 1500m/s indicate the distance between the ultrasonograph’s head and the tissue from which the sound was reflected. 

Indicate proper assignments:

At a defined frequency (1000 Hz) the sensation of sound loudness is: 

At the basilar membrane in the inner ear:

 Indicate the channel which is crucial in converting the mechanical signal (sound) into the electrical one at the cilia in the hair cells:

In which conditions a proton in the presence of external magnetic field (Bo) is in the state characterized by the highest energy (u is the magnetic mment of the proton)

Acetylcholine released from vagus nerve onto SA node cause: 

he relaxation time T1 is determined in t he experimental protocolin which(symbols: M2

is the component of magnetization M parallel to external magnetic field B.. rf 90 degrees

pulse – radio frequency electromagnetic wave with magnetic coponent perpendicular to B..) 

 Infrasounds (find true sentence)

Doppler effect can be used for 

Corpuscular radiation is 

A standard ECG is recorded from 12 following leads:

If the intra- and extracellular concentrations of a considered ion are equal, the Nernst equilibrium potential for this ion is equal to:

 The current density for a considered ion is: J=O delta V/delta X 

The resting membrane potential occurs in conditions in which: 

If the intracellular concentration of chloride ions increase, the resting membrane potential:

Indicate which effect on the action potential time course would have the impairment of the inactivation process (ex. scorpion venom) in the voltage-gated sodium channel?

Where are localized the acethylcholine receptors at the neuromuscular junction? 

 Choose the best characteristic of myothonia congenita: 

Figur represents dipole. What is the value of electrical potential at the position indicated as “R”?

Indicate the type of channel responsible for a slow depolarization of the diastolic potential in the SA-node.

Arterial blood pressure is: 

Which ultrasonographic mode is used to record 2D image? 

What would you use to ionize gas? 

If 1 photon hit a cone, what would this do? 

rods are more sensitive to light than cones by how many time? 

if you double the radius of a lens what will happen to the optical power? 

At the peak of the action potential what current predominates? 

At hyperpolarization what current predominates? 

half life is 50 years, how much time would pass for 1000 moleculces to decay to 125? 

Rock 3km from submarine, how much time needed for the echo to come back when it travels at 1500m/s?

High frequency are recognized by which part of the basilar membrane? 

What happens to the dark current when light hits the cell? 

what would happen to blood flow if you increase the diameter of a vessel 3 fold? 

Correct juxtaposition:

Total optical power of a human eye is? 

If the focal point is 10 cm in front of the eye then the optical power of the eye is?