Answer:
15.75 cm
Explanation:
focal length of convex lens, f = + 9 cm
position of object, u = - 21 cm
Let the distance of image is v.
Use lens equation
1 / f = 1 / v - 1 / u
1 / 9 = 1 / v + 1 / 21
1 / v = 1 / 9 - 1 / 21 = (21 - 9) / (21 x 9)
1 / v = 12 / 189
v = 15.75 cm
Answer:
Explanation: We have seasons because Earth's axis – the imaginary line that goes through the Earth and around which the Earth spins — is tilted. It's tilted about 23.5 degrees relative to our plane of orbit (the ecliptic) around the Sun. As we orbit our Sun, our axis always points to the same fixed location in space. Our northern axis points almost directly toward Polaris, the North Star.
A Beam balance (or Beam scale) is a device to measure weight or mass. These are also known as mass scales, weight scales, mass balances, weight balances, or simply scales, balances, or balance scales. You can also use a graduated cylinder and determine the water displaced and figure out the mass of an object this way!
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Answer:
1. The nucleus is about 1/2 the size of the atom
Explanation:
Alpha particles are positive charge particles and they are bounced back by the nucleus because nucleus is also same size
Now in present experiment Rutherford found that very few alpha particles are bounced back along same path which shows that very small region inside the nucleus is having positive charge and rest part of the atom is empty.
Now if we found that half of the alpha particles are bounced back then it shows that size of the nucleus is very large now as compare to previous one because only nucleus can bounce back the alpha particles
so correct answer will be
1. The nucleus is about 1/2 the size of the atom
C is the best answer
hope it helped