high school physics worksheets with answers



for gamma radiation, what stops its penetrating abilities?

Gamma radiation can only be stopped by a thick concrete of a block
 A gamma radiation has the highest energy and it is the most penetrating,  it can pass through thin of paper , aluminum human skin etc , it can only be stopped by a thick concrete of aluminum block.
 A better particle is also highly penetrating but not as much as that of alpha, it can pass through  thin sheet of paper, move several  hundredths of centimeters in air  but can be stopped by a thin sheet of aluminum.
 While an alpha ray is the least penetrating it can be stopped by a a sheet of paper and only raveled few centimeters into the air.


which type of radiation has the lowest penetrating ability?

 The radiation with the lowest penetrating ability is alpha ray,
 It is the most massive and most ionizing, it can easily be stopped by a thin sheet of paper.
 The large mass of alpha particle  makes its length passage through  other matter very minutes,   the  alpha particle is equivalent to the size of a helium nucleus, it a mass of about 4 amu , it hs to protons and two neutrons compared to beta particle which is just an electron and a gamma it it completely massless .
It large charge make it highly ionizing, this is why it can easily ionize any substance it come into contact with it.
  It penetrate least because anytime it come into contact with other matter, it has to release loses energy due to friction and charge ionization
 The large mass and large charge makes an alpha particle the least penetrating .

for beta radiation, what stops its penetrating abilities?

 a beta particle can be stopped by a thin  sheet of aluminum, it has minutes mass, just a mass of electron and a charge of negative one.
 It small mass allows it move several centimeters in air and other to penetrate other matter with less friction that will consume the its energy,
 It little charge makes it to ionize with particle it come in contact with it,
  when a beta particle had a contact with a substance it loses some energy use to ionization, this is why it doesn’t penetrate much into other matter.
  The charge and mass of beta particle affect the ability of the beta particle to easily pass through matter like gamma.
 Gamma has no charge or mass, therefore it doesn’t have any friction or ionizes matter when it passes through.

what percentage of a radioactive species would be found as daughter material after five half-lives?

When a radioactive specie undergo a half-life, it loses it original mass by half or by 50 percent and will be left by half r 50%.
 After the 1st half life we wil be left wit  50% of the original mass
 After a second  halflife, we will be left with 25% of the orginal mass, half of the remaning 50 percent will also decay by half. We have now lost 75% of the orinal mass after two half life .
 After the third half , 50% of the remain 25% will also go and we will be left with 12.5% , we have lost 87.5% of the original mass.
After another halflife  50% of the remaining 12.5% will also decay  and we will be left with  6.25% therefore  93.75% of the original  mass has disappeared.
 At the 5th halflife half of the remaining 6.25% will also disappear and we will be left with 3.125%.

can two atoms with the same mass be isotopes of each other

 two atoms with the same atomic number but different mass number are called isotopes, atoms with the same  masses but different mass numbers are called isobars.
 Two atoms with the atom with the same number of protons but different  number of neutron are what are called isotopes. The isotopy occur due to difference in the number of  neutron between the two atoms.
 Two atom with the same atomic number but and  same mass number cannot be called isotopes but a single atom.

do all isotopes of an element have the same atomic number

 all isotopes of the same element have the same atomic number, they have same number of protons in their nucleus and exhibit the same chemical properties.
  The number of protons in the nucleus of an atom is the atomic number while the  sum of the protons and the neutrons in the nucleus of an atom is the mass number.
  What cause isotopy in an element is the difference in the number of neutrons between two or more of its atoms,  his is nothing but just the difference in te numbr of neutrons.
 Therefore all isotopes of an element have the same  atomic number , all isotopes of the same element have different mass number.
 All isotopes of the same element have different nuclear properties.

in a neutral atom how does the number of electrons compared to the number of protons

 in a neutral atom, atom that is not ionized, in other words , a neutral atom is any atom that does accept or reject any electron.
A neutral atoms have equal number of protons to electrons and protons, the electrons are  negatively charge and the protons are positively charged.
 For an atom to be electrically neutral, the negative and the positve must cancel-out. In other word each protons has a charge of + one and each electron has a charge of -1,
 Therefore if we have 20 protons, we have + 20 charges and we will need like -20 charges to cancel-out all the charges and have a neutral atom.

can two atoms with the same mass number ever be isotopes of each other

atoms with the same atomic mass can never be isotopes to each other, but can only be isobars atoms with different atomic number but the same mass number, isobars. Isobars are created by beta, positron   decays and electron captures.
All these process increases or decreases atomic number  of the original atoms but the mass number remain constant, the new atoms formed therefore have the same mass number with the original atoms while having different  atomic numbers.

235 92u+10n→azba+9436kr+310n enter the isotope symbol for the barium (ba) nucleus in this reaction.

 Let us write the equation first
23592U+1 0n→azBa+9436Kr+310n
 For a nuclear equation to be balanced, the superscript and the subscript must on the left hand side and the right hand side must be equal, in other words the sum of the  atomic number on the left hand side must be equal to sum of the atomic numbers on the right hand side and the sum of the mass numbers on the left hand side must be equal to the sum of the mass numbers on the right hand side.
 The nuclear equation above the super script, we have
 235 +1  =a+94+3(1)
236 = 97 +a
 Therefore,
 a=236-97= 139
and for the subscript
 we have
92 +0 = z + 36+ 3(0)
92= 36+z
Z = 92-36
Z= 56
 Therefore the above equation can be rewritten as

 23592U+1 0n→13956Ba+9436Kr+310n
13956Ba


enter the nucleus that produces bismuth-211 by beta decay.

 Let us write the decay equation first
? 211 83Bi + 0 -1e
 During a beta decay ,  a neutron decayed into a proton, the atomic number increases by one while the mass number decreases by  remain unchanged, the daughter nuclide formed will have an atomic number greater than that of the parent nuclide by one.
 From the above equation the daughter nuclide is bismuth with atomic number of  83, the parent nuclide will have an atomic number of 82 and the atom that fit the above description is lead
 We can therefore , rewrite the above equation as follows
21182Pb21183Bi + 0 -1e

give the symbol for a neutron.

  This the symbol of neutron
10n

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