All categories

3 years ago

Which of the following is not a necessary condition for seeing a magnified image with a

1 answer:

5 0

The option stating that the observer must be placed within the focal length is false or not a necessary condition for magnification.

Explanation:

Lens are used for magnification provided the nature of the lens is known and by positioning the object at correct position. So the object should be placed in the focal point of the lens for perfect magnification, it can also be kept within the focal point or focal length. But the object should not be kept beyond the focal length of the lens.

So among the given options, the object and image should be on the same side of the lens for magnification is true. Then the nature of lens should be converging for magnification is also true. And the most important point that the object should be placed within the focal length of the lens is the most mandatory for obtaining magnification. So the option stating that the observer must be placed within the focal length is false or not a necessary condition for magnification.

You might be interested in

10) The closest star to the earth (other than

Reptile [31]

Answer:

It takes a little, be patient.

8 0

4 years ago

Two spherical asteroids have the same radius R. Asteroid 1 has mass M and asteroid 2 has mass 1.97·M. The two asteroids are rele

nekit [7.7K]

Answer:

$0.536\sqrt{\frac{GM}{R}}$

Explanation:

We are given that

Mass of one asteroid 1, $m_1=M$

Mass of asteroid 2, $m_2=1.97 M$

Initial distance between their centers,d=13.63 R

Radius of each asteroid=R

d'=R+R=2R

Initial velocity of both asteroids

$u=0$

We have to find the speed of second asteroid just before they collide.

According to law of conservation of momentum

$(m_1+m_2)u=m_1v_1+m_2v_2$

$(M+1.97 M)\times 0=Mv_1+1.97Mv_2$

$Mv_1=-1.97 Mv_2$

$v_1=-1.97v_2$

According to law of conservation of energy

$Gm_1m_2(\frac{1}{d'}-\frac{1}{d})=\frac{1}{2}m_1v^2_1+\frac{1}{2}m_2v^2_2$

$GM(1.97M)(\frac{1}{2R}-\frac{1}{13.63R})=\frac{1}{2}M(-1.97v_2)^2+\frac{1}{2}(1.97M)v^2_2$

$1.97M^2G(\frac{13.63-2}{27.26R})=\frac{1}{2}Mv^2_2(3.8809+1.97)$

$1.97MG(\frac{11.63}{27.26 R})=\frac{1}{2}(5.8509)v^2_2$

$v^2_2=\frac{1.97GM\times11.63\times 2}{27.26R\times 5.8509}$

$v_2=\sqrt{\frac{1.97GM\times11.63\times 2}{27.26R\times 5.8509}}$

$v_2=0.536\sqrt{\frac{GM}{R}}$

Hence, the speed of second asteroid = $0.536\sqrt{\frac{GM}{R}}$

8 0

3 years ago

8. Contrast. The energy that can be released during a nuclear fission reaction with the energy that can be released during a nuc

Cloud [144]

8) the energy released by fusion is generally 3 to 4 times larger than with fission. Fission has very few by-products but fusion releases large amounts of radioactive particles because it starts with large nuclei.
9) Alpha particles are 2 protons and 2 neutrons all put together. It's really the nucleus of a helium atom. It is most dangerous if you ingest it but it can be stopped with a sheet of paper so outside the body it's not as dangerous as others and due to its size it can't get very far in the air before hitting air molecules
beta particles are high energy electrons or positrons. They travel further due to their small size but can be stopped by a thin barrier of plastic or wood.
Gamma rays are high frequency photons (light) They are stopped by metal plates and go through human tissue. They are quite dangerous.
10) The mass that is lost in chemical reactions is very small. Solve E=mc² for mass and you get m=E/c². This says the mass you lose is equal to the energy you gained divided by the speed of light squared. c² is a VERY big number so you need a lot of energy produced to notice it. Chemical reactions are simply too inefficient to get that much energy out.
11)You need high temperatures for fusion because you're trying to push two atoms together (to "fuse" them as the name suggests) The electrons in one atom repel the other electrons in the other atoms. When stripped down to only protons, you still have to overcome this repulsion (Coulomb repulsion). High temperatures means high velocity of the particles in the plasma. This gives them enough "oomph" to get close enough to fuse. Once close enough to each other, the nuclear force takes over and overwhelms the Coulomb repulsion and the nuclei fuse and release energy in doing so.

7 0

3 years ago

Elements in which family are most likely to have properties associated with

Elena-2011 [213]

Answer: As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals.

Alkaline earth metals

The alkaline earth elements are metallic elements found in the second group of the periodic table

Explanation:

5 0

4 years ago

The train is accelerated from rest at a speed of 0.11 m/s2 to reach a speed of 15.6 m/s. After reaching that speed the train mov

9966 [12]

Answer:

cliff

Explanation:

7 0

3 years ago