Prep 1 revision

find the mass number of the opposite diagram?

• 38

• 40

• 18

• 20

An element whose electrons are distributed in three energy levels, and the outermost energy level carries 3 electrons and its atom contains 14 neutrons, does this element share in chemical reactions?

• Yes

• No

one gram of ................... contains one type of atoms.

• iron

• ammonia

• water

• hydrogen chloride

when the object is thrown upwards its ..............

• speed increases gradually

• speed decreases gradually

• kinetic energy increases gradually

• potential energy decreases gradually

the mechanical energy of a pendulum at the maximum displacement equals ...............

• its kinetic energy

• kinetic energy + potential energy

• its potential energy

• zero

the simple electric cell contains ..............

• dil. HCl

• $HNO_3$

• dil. $H_{2_{ }}SO_4$

• NaCl

the heat of the heater is transferred by ...............

• conduction and radiation

• radiation and convection

• conduction and convection

• radiation only

As an object falls down ...............

• the potential energy increases

• the mechanical energy is lost

• the speed of the object decreases

• the kinetic energy increases

................ is what cooks your food inside the microwave.

• conduction

• convection

• conduction and convection

• radiation

the electric current in the simple electric cell passes from the .....................

• positive copper plate to negative zinc plate

• positive zinc plate to negative copper plate

• negative zinc plate to positive copper plate

• negative copper plate to positive zinc plate