Question Discussion & Solution

CONCEPT:

Rutherford’s Model of the Atom:

• He bombarded the beam of alpha particles on a very thin gold foil.
• While bombarding he observes the number of scattering of particles –
  • Most of the particles passed either un-deviated or with a very small deviation.
  • Some deviated by large angles
  • 1 out of 8000 was deflected by more than 90°
• The conclusion to this deflection:
  • Most of the space of an atom is empty.
  • At the centre of an atom having a tiny positively charged particle called a nucleus.
  • The centre nucleus has all the mass of an atom.
  • The amount of positive charge at the nucleus is equal to the total amount of negative charges on all the electrons of the atom.
  • All the electrons revolve around the nucleus and coulomb force provide the centripetal force

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EXPLANATION:

• After the α -particles scattering experiment, the following conclusions were made by Rutherford as regard as atomic structure:

• Most of the mass (at least 99.95%) and all of the charge of an atom concentrated in a very small region is called the atomic nucleus. Therefore option 4 is correct.
• The nucleus consists of proton and neutron, in which proton was first discovered by Rutherford but neutrons were later discovered by James Chadwick in 1932.
• In an atom, there is maximum empty space and the electrons revolve around the nucleus in the same way as the planets revolve around the sun and the nnumber of protons and electrons inside an atom are equal under normal conditions (non-ionized). 

• Becquerel is the SI unit of radioactivity.
• 1 Becquerel = 1 disintegration/Second
  • Disintegration: As the radioactive elements are unstable they will disintegrate at any moment by emitting alpha or beta particles and form new elements called daughter elements which are completely different in both physical and chemical properties when compared to the elements they came from.
  • The rate of disintegration does not depend upon external factors like temperature, pressure, etc.

In a certain code language, 'CLASS' is written as 'DMBTT'.

Similarly, 'BLUE' written in that code language as

BLUE is related to CMVF.

Hence, "CMVF" is the correct answer.

A keyboard is for putting information including letters, words, and numbers into the computer. A keyboard's primary function is to act as an input device. Using a keyboard, a person can type a document, use keystroke shortcuts, access menus, play games and perform a variety of other tasks.

Key Points

• A modifier key is a key on a computer's keyboard that's only used in conjunction with another key.
• Modifier keys are often used with other keys to perform computer keyboard shortcuts and other commands.
• For example, in many text editor programs pressing the Ctrl+A selects all text.

Additional Information

• The function keys or F keys are lined across the top of the keyboard and labeled F1 through F12. These keys act as shortcuts, performing certain functions, like saving files, printing data, or refreshing a page.
  • For example, the F1 key is often used as the default help key in many programs. The F5 key is used in an Internet browser to refresh or reload a web page. The function of these keys can differ by the operating system and by a software program.
• A special key or media key, or multimedia key is a keyboard key that performs a special function not included with the traditional 104-key keyboard.
  • For example, the picture shows a Logitech keyboard.
• An ergonomic keyboard is a keyboard designed for comfort, ease of use, and reduced strain on the user.
  • Such keyboards may include features like concave or tapered keys, keys that are well-spaced, or keys that separate and angle out from a central pivot point.

Therefore, based on the above information The keys of a keyboard, which are used to modify the input of other keys, are called modifier keys.

SRAM (static RAM) is random access memory (RAM) that retains data bits in its memory as long as power is being supplied.

Inside a dynamic RAM chip, each memory cell holds one bit of information and is made up of two parts: a transistor and a capacitor.