اختبار تجريبي (2) لمادة العلوم للصف الثالث متوسط الفصل الدراسي الثاني لعام 1438-1439

Explanation
If a tomato diploid cell contains 24 chromosomes, then its gamete cell would contain half of that number, which is 12 chromosomes. This is because gametes are haploid cells, meaning they only contain one set of chromosomes, while diploid cells have two sets. Therefore, the correct answer is 12.

Explanation
The given statement is incorrect. The process described in the statement is actually called photosynthesis, which is the process by which plants convert chemical energy into light energy.

Explanation
The given statement is incorrect. It states that there is only one type of reproduction, which is asexual reproduction. However, this is not true as there are two types of reproduction: sexual reproduction and asexual reproduction. Sexual reproduction involves the fusion of gametes from two parents, resulting in offspring with genetic variation. Asexual reproduction, on the other hand, involves the production of offspring without the involvement of gametes or the fusion of genetic material.

Explanation
The correct answer is "فولت". Volt is the unit of measurement for electric potential difference or voltage. It is named after the Italian physicist Alessandro Volta, who invented the first electrical battery.

Explanation
A magnet has two poles, a north pole and a south pole. These poles are where the magnetic force is strongest. Therefore, the correct answer is 2.

Explanation
In the magnetic field, an iron bar is used to enhance it.

Explanation
The given statement is correct. The Earth's magnetic field acts as a protective shield against charged particles coming from the Sun. These particles are deflected by the magnetic field, preventing them from directly reaching the Earth's surface. This magnetic field plays a crucial role in protecting our planet and its atmosphere from the harmful effects of solar radiation.

Explanation
السرعة المتجهة تشير إلى مقدار السرعة واتجاه الحركة للجسم. فهي تعطي معلومات حول سرعة الجسم والاتجاه الذي يسلكه في نفس الوقت. على سبيل المثال، إذا كان الجسم يتحرك بسرعة 50 كم/س شمالاً، فإن السرعة المتجهة تكون 50 كم/س شمالاً.

Explanation
The statement is saying that gold and copper are examples of materials that conduct electricity. This is true because both gold and copper are known for their high electrical conductivity. Gold is an excellent conductor of electricity due to its low resistance, making it commonly used in electrical connectors and circuitry. Copper, on the other hand, is widely used in electrical wiring and transmission lines because of its high conductivity and affordability. Therefore, the given answer "صح" (true) is correct.

Explanation
The given statement is incorrect. It states that displacement for motion is the distance between the starting point and the ending point, which is not true. Displacement refers to the change in position of an object and is a vector quantity that takes into account both the distance and direction between the initial and final positions.

Explanation
في دائرة التوصيل على التوالي، يوجد مسار واحد فقط للتيار الكهربائي ليسير خلاله. في هذا النوع من الدوائر، يتم توصيل المكونات الكهربائية بشكل متتالي حيث يمر التيار من مكون إلى آخر بدون تفرع. لذلك، لا يوجد أكثر من مسار للتيار الكهربائي في دائرة التوصيل على التوالي.

Explanation
The correct answer is "أيون" (ion). An ion is an atom that has gained or lost electrons, resulting in a positive or negative charge. In this case, the question is asking for the term used to describe a charged atom, and the correct answer is "أيون".